Wikipedia:Peer review/Nonmetal/archive1

Nonmetal


I'm submitting this article for peer review prior to listing it for a second time at FAC.

It was first put up for FAC on July 20, 2021 and closed after six days. Pre-closure, all concerns had been addressed bar two minor requests that I didn't see prior to closure.

The two minor correction have been fixed. There has been some further (minor) copyediting: a dozen edits in sum.

Thanks, Sandbh (talk) 05:34, 2 August 2021 (UTC)

Esculenta

 * Hi Sandbh, here is some nit-picky WP:MOS advice that should help the article with its next FAC:


 * ensure all book titles are consistently in title case (e.g. “Chemistry: The study of Matter and its Changes” and “Fundamentals of chemistry” need slight adjusting). Journal article titles are typically sentence case, but it doesn’t really matter as long as it’s consistent throughout.
 * Done. Sandbh (talk) 04:28, 9 August 2021 (UTC)


 * ensure that the page ranges are given in consistent format (e.g. pp. 609–614 vs. 411–13)
 * Done. Good pick. Sandbh (talk) 00:15, 9 August 2021 (UTC)


 * ensure that page ranges use an endash, not a hyphen
 * Done. See below. Sandbh (talk) 00:15, 9 August 2021 (UTC)


 * ensure all of the "pp."s are correct (e.g. I saw the incorrect "p. 24–25" and "p. 3-32")
 * Done. I checked them all for consistency and made a few corrections. "p. 3-32" was OK since the page is numbered that way. Sandbh (talk) 12:47, 8 August 2021 (UTC)


 * there’s some inconsistency as to whether a page is given in the "Citations" or in the “Bibliography” (e.g. see "McMillan 2006": no page in the citations, page # given in Bibliography. In "Bell & Garofalo, p. 131" the page number is given in both sections. In Ritter 2011, the page number is given in the Bibliography, not the citations, and a page range for the entire article isn't shown, as would be expected. Needs to be consistent throughout.
 * Comment: I believe my approach is if the citation is to a specific page or to specific pages I list it in the citation. If it is to a whole article, or a whole chapter in a book, I list the page range in the Bibliography. I'll check this for consistency. 219.90.178.191 (talk) 04:27, 9 August 2021 (UTC)
 * Comment. I was wrong. WP:CITE says page ranges are to be included in the short citation, not in the bibliography. Sandbh (talk) 07:34, 9 August 2021 (UTC)
 * Done. Sandbh (talk) 08:23, 9 August 2021 (UTC)


 * "Rudolph J 1974, Chemistry for the Modern Mind, Macmillan, New York: "...oxygen and the halogens in particular...are therefore strong oxidizing agents."" here a quote has been given in the bibliographic citation, ostensibly to support a statement given in the text, but this is not the correct formatting for a supporting quote (should be given in the citation section, or in the notes)
 * Comment. AFIAK there is no wp-policy for supporting quotes or where they should appear. I may be wrong and will look again. Sandbh (talk) 04:28, 9 August 2021 (UTC)
 * Comment. I was wrong. WP:CITE says quotes are to be included in short citations. Sandbh (talk) 07:34, 9 August 2021 (UTC)
 * Done. Sandbh (talk) 08:23, 9 August 2021 (UTC)


 * there are several duplicate links. Some might be justifiable, given the amount of text separating successive links, but it will be mentioned at FAC and so should be double-checked.
 * Done Sandbh (talk) 04:46, 9 August 2021 (UTC)


 * suggested links for lead: conductor, bromine
 * Done, thank you. Sandbh (talk) 04:46, 9 August 2021 (UTC)


 * in the "Discovery" section, two people are referred to with last name only, while another two have their full name used - should be consistent
 * Done. Sandbh (talk) 04:28, 9 August 2021 (UTC)


 * "a single crystal of produced via chemical vapor transport can cost..." missing word
 * Done. Sandbh (talk) 04:28, 9 August 2021 (UTC)

Sorry, I don't have any substantive commentary about article content (not my field), but I hope these suggestions will help nonetheless. Esculenta (talk) 17:06, 6 August 2021 (UTC)
 * Thank you Esculenta. That kind of feedback is gold! Sandbh (talk) 00:51, 8 August 2021 (UTC)

Graeme Bartlett

 * Some opinions:
 * The split of the references into citations and Bibliography adds complexity for editors and difficulty for our readers, so best if it was hitting the full reference information when one licks the footnote.
 * Comment Thank you Graeme. I've seen and used both kinds of citation systems, including in FA. WP:FACR 2c. says:
 * "consistent citations: where required by criterion 1c, consistently formatted inline citations using footnotes—see citing sources for suggestions on formatting references. Citation templates are not required."
 * WP:CITE includes provision for the use of the short citation system, as employed in Nonmetal. Unless I've missed something. or there's a "hidden FAC rule" that says otherwise, I propose to retain the short citation system. Sandbh (talk) 06:30, 9 August 2021 (UTC)
 * In complications paragraph, "first row anomaly" and "alternation effect" are mentioned but apparently remain unexplained. Probably the text in that section does explain it, but the explanation is unlinked to the term.
 * Done. Sandbh (talk) 06:05, 9 August 2021 (UTC)
 * "Astatine and tennessine" should mention that their bulk properties are unknown or unknowable, rather than just an expectation.
 * Done. Sandbh (talk) 06:05, 9 August 2021 (UTC)
 * For the "Property spans and average values for the subclasses of nonmetallic elements " table, it is not so easy to navigate as the properties are in there as centred subheaders, it would be better to have them on the left.
 * Done.
 * The second paragraph starting "Of the twenty-three elements" is excessively complex and appears to have a syntax error, though perhaps it is technically correct and just too difficult to read.
 * Done. Good call. Sandbh (talk) 07:09, 9 August 2021 (UTC)
 * Checking facts about hydrogen and helium being 98%, I want to know is that by mass or count of atoms. The source does not confirm,, It says 99% and 75% hydrogen and 25% helium, without mentioning if it is by mass. A better source should be used.
 * Done. Good observation. Sandbh (talk) 06:05, 9 August 2021 (UTC)


 * Where possible please give a URL to link to for sources, eg Lifting the Scientific Veil: Science Appreciation for the Nonscientist by Paul Sukys is on Google books
 * Comment: I do this where possible but not to GB as they are unstable. From personal experience, GB varies which pages are viewable. A page that may be visible on one day, either fully in snippet view, may not be available the next time. WP:CITE provides that:
 * "Google Books sometimes allows numbered book pages to be linked to directly. Page links should only be added when the book is available for preview; they will not work with snippet view. Keep in mind that availability varies by location. No editor is required to add page links."
 * Of course, I may be overlooking a "hidden FAC rule" that says otherwise. If so, I'd be happy to oblige. Sandbh (talk) 07:25, 9 August 2021 (UTC)

Graeme Bartlett (talk) 22:23, 7 August 2021 (UTC)


 * Thank you Graeme Bartlett. This kind of feedback is precious and much appreciated! Sandbh (talk) 00:51, 8 August 2021 (UTC)

From FAC
I'm pasting here some of the comments I made at the FAC and their replies (verbatim), not all of which have been addressed prior to its closure. I also haven't had a chance to fully review them or other sections of the article in that timeframe, so my replies and additional comments may not follow any particular order.
 * Comment. I've added my assessment of the status of each item. Sandbh (talk) 06:45, 9 August 2021 (UTC)


 * 1. We should firmly establish an WP:ENGVAR, then do a full copyedit and MOS check. I, and a few other editors, have made a few minor MOS fixes over the past few weeks.
 * 2. Section Origin and use of the term – more citations needed, one in the footnote won't cut it.
 * 3. – citation needed. Also, though summary-style is a fundamental component of an article like this, this really feels rushed and doesn't read too well. It introduces some more technical terms such as specific heat capacity (?) with which a layperson may not be familiar, at least not before reading the section on properties. Could also use more wikilinks (such as the one I linked here if that's correct) and a few other MOS fixes.
 * 4. – inline citation needed, preferably from Lavoisier himself.
 * 5. Section Properties – it might be helpful to introduce some of the more technical terms, or at least what they mean in a practical (application) or observational sense. I'd do this before highlighting the contrast with metals.
 * 6. – I wouldn't use the term nearly all when 6/17 (or 12/23 if metalloids are counted as nonmentals) are solid or liquid. If this was not the intended meaning, parts of this paragraph may need to be written. The next part of the sentence,, could also be covered under the nearly all...; I suggest breaking up this run-on sentence.
 * 7. – with a bit of rephrasing, this would be a good place to start a new sentence.
 * 8. – this may be clearly presented in a data table, but an inline citation is needed here.
 * 9. – what conditions?
 * 10. – WP:SELFCITE, especially when saying generally regarded. To fix this, I suggest having another editor review and perhaps elaborate on this, as well as additional citations from other authors to make it clear that this really is a generic statement.
 * 11. – inline citation needed, preferably from Lavoisier himself.  oops
 * 12. – reported by whom? Also, for such a short section, this really feels like undue emphasis on the recent classification of one author. Has the subset of unclassified nonmetals been historically considered as such? This section could also be expanded to describe the various classifications of these elements.
 * 13. Section Nonmetal halogens – also feels too short and only has one inline citation (plus another in a footnote).
 * 14. – too colloquial. This would read better as "In periodic tables, they occupy the rightmost column" or something similar. It's a fairly straightforward fix, but I just included it as an example for 1a.
 * 15. – citation needed.


 * This is not an exhaustive list, but I hope this gives a clear(er) idea of where this article still needs some considerable work before meeting FAC standards. I'm not sure how much time I'll have to commit to the review process (whichever it may be), but I'll happily nitpick specific sections or help with copyediting in the next couple of weeks. ComplexRational (talk) 15:26, 22 July 2021 (UTC)

Thank you ComplexRational, including for your interim oppose. I'll address your observations shortly. Sandbh (talk) 05:07, 23 July 2021 (UTC)

ComplexRational: I've numbered your dot points, and my mine, to make things easier to follow.

0. Done. Re: "…it is still being heavily edited and expanded" — since posting to FAC, and judging by eye, the sizeable majority of edits have been to add citations (49 now added), the rest has been some trims, converting some text to a table; and some ce's. B4 posting the article at FAC, criteria for FAC and MOS were checked, including the requirements for support by inline citations where appropriate. The article was GA when work started to bring it up to FA standard. This involved trimming from 125K to 89K; rearranging and refining existing content into 3 to 4 classes; and adding citations and notes. Copyediting was undertaking several times.
 * 1. Done. The language variety was checked pre-FAC and found to be US. That being so, no language notification was posted. Spelling was checked and corrections made for US language.
 * Was it? I still see mixing of en-US and other varieties. We have both oxidize and recognised, as well as vapour, and inconsistent use of, for instance aluminum, potassium and iron and chlorine, bromine, and iodine. One way or the other, this should be consistent. If we go for en-US (if ENGVAR permits), I'll help with the copyediting.
 * Done. Yes, it was, manually, in the absence of a tool. After pasting into Pages (Word not permitting a language change), and picking US Eng., ca. 17 further instances of non-US spelling have now been amended. "Aluminium" is the IUPAC spelling. Sandbh (talk) 04:54, 24 July 2021 (UTC)
 * The WP style is documented in MOS:ALUM YBG (talk) 05:20, 24 July 2021 (UTC)
 * I think you meant WP:ALUM. ComplexRational (talk) 21:53, 8 August 2021 (UTC)
 * 2. Done. The Origin and use of the term section was/is supported by four citations, rather than one. To make this clearer a note has been added saying, "(see the taxonomy table in this section)".
 * 3. Done. A citation referring to the basicity of quicklime has been added. "Specific heat capacity" was/is nowhere used in the article
 * Citation looks good. I only mentioned specific heat capacity because I'm not sure if that's what you meant by capacity to conduct heat – be it correct or incorrect, a wikilink would help here if there are technical details to discuss.
 * Changed to "ability to conduct heat"; link added to thermal conductivity. Sandbh (talk) 04:54, 24 July 2021 (UTC)
 * 4. Done. Subſtances ſimples non-métalliques and métalliques had no inline citation since the work in which these words appeared i.e. Traité élémentaire de chimie was wikilinked in the same sentence. A citation can be added if this will not represent citation overkill?
 * It won't be citation overkill because the article currently states that Lavoisier described nonmetals as such, but not actually sourcing this claim directly. Only if both Lavoisier's work and a secondary source describing that were included would there possibly be overkill.
 * Thanks; citation added. Sandbh (talk) 04:54, 24 July 2021 (UTC)
 * 5. Done. Section  Properties. Technical terms in this section were/are wikilinked.
 * 6. Done. goes on to say—as noted above—"or polyatomic solids". Here, of 23 nonmetallic elements all but Br are diatomic or monatomic gases, or polyatomic solids. The sentence has been edited and broken up into two smaller sentences.
 * Better now, no longer ambiguous. ComplexRational (talk) 21:53, 8 August 2021 (UTC)
 * 7. Done. —as above
 * Also reads better now.
 * 8. Done. —cite added.
 * 9. Done. —copy edited and wlink added.
 * 10. Done. —That the subject elements are too diverse for a collective examination has been discussed and acknowledged on and off for about the past ten years at WP:ELEM. Four more citations have been added to this effect—two specific across four authors and three referring to the expression "other nonmetals".
 * 11. Done. "– inline citation needed, preferably from Lavoisier himself." Lavoisier (1789) only distinguished between metals and nonmetals. As discussed at WP:ELEM over ten years, there is no record in the literature of a widely accepted name for the unclassified nonmetals. Citations are now there for the originators of the names metalloid, halogen, and noble gas.
 * My mistake on including Lavoisier here (oops), I meant that in point 4 with Lavoisier's quote. In the case of there not being a widely accepted name, it would be best to give equal weight (NPOV/UNDUE) to the most commonly used names. The citations you added look good at first glance, as does the mention of other nonmetals.
 * Thanks for that. Sandbh (talk) 04:54, 24 July 2021 (UTC)
 * 12. Done. "– reported by whom?" Reported by: Cao C, Vernon R, Schwarz E, Li J 2021, " Understanding periodic and non-periodic chemistry in periodic tables", Frontiers in Chemistry, vol. 8, 10.3389/fchem.2020.00813. The nonmetal article states: "After the nonmetallic elements are classified as either metalloids, halogens or noble gases, the remaining seven nonmetals are hydrogen, carbon, nitrogen, oxygen, phosphorus, sulfur and selenium."
 * The proposal to refer to "unclassified nonmetals" was notified to WP:ELEM and well received. If followed the decision by WP:ELEM to deprecate the use of fixed colour categories in the lede periodic table appearing in that article in order to provide more flexibility in discussing sets of elements, and given how many variations there are in the literature around the borders aside from the alkali metals in group 1. As noted, the unclassified nonmetals are what is left after the nonmetallic elements are classified as either metalloids, halogens or noble gases. A basic taxonomy of the nonmetals involved was set out in 1844 by Dupasquier. To facilitate the study of metalloids (i.e. nonmetals), he wrote that, “they will be divided into four groups or sections, as in the following: Organogens (O, N, H, C); Sulphuroids	(S, Se, P); Chloroides (F, Cl, Br, I); 4th	Boroids	B, Si." But his taxonomy never caught on. See: Dupasquier, A.: Traité élémentaire de chimie industrielle. Charles Savy Juene: Lyon, 1844, pp. 66–67. Since that time the closest there is in the literature is to the "other nonmetals", as supported by three citations. There is a wp article on the CHON elements and CHONPS, however this does not cover Se. The pre-FAC version of nonmetal surveyed various arrangements of the nonmetals. Since none of these caught on in the literature, whereas metalloids are, albeit inconsistently; and halogens and noble gases are universal, and that leaves the unclassified nonmetals, the previous various arrangements of the nonmetals were left out of the current iteration of nonmetal. They could easily be spun out into their own child-article if preferred.
 * Re "This section could also be expanded to describe the various classifications of these elements", a new article has been created, List of alternative nonmetal classes, and a foonote added to Nonmetal. Sandbh (talk) 03:45, 25 July 2021 (UTC)


 * 13. Done. "Section Nonmetal halogens – also feels too short and only has one inline citation (plus another in a footnote)" — It is short as it has its own hatnote referring to the Halogen main article. Four more citations have been added.
 * 13a. Done. – page range too wide, this is the entire chapter on halogens, can you narrow it down or include multiple cites?
 * 13b. Done. – I skimmed some of that chapter while checking the source, and I see many types of bonds on a spectrum from ionic to covalent are described (p. 823, for instance). Perhaps this might be worth a brief mention somewhere if it's pertinent in the context of nonmetal chemistry. Also, although it's in the table already, you might want to note that O is an exception to the remaining nonmetals (i.e., it forms mostly ionic compounds with metals) because of its high electronegativity. This looks like a very nuanced matter, though, so the more intricate details can be saved for a sub-article.
 * 14. Done. " – too colloquial. This would read better as "In periodic tables, they occupy the rightmost column" or something similar." — What is colloquial and what is more formal will vary from person to person. For example, "In periodic table terms" appears in the FA periodic table article. The former + "outermost right column" appear in literature. The accompanying table further illustrates the location of the noble gases in the outermost right column. I have edited the passage in question.
 * Reads much better now. Indeed formality is subjective, and different authors have their own unique style. I also find sometimes that it's not only a matter of formality, but when the same ideas can be equally well described with fewer words, it's usually better to do so.
 * Thanks for that. Sandbh (talk) 04:54, 24 July 2021 (UTC)


 * 15. Done. " – citation needed." – Extant citation relocated.
 * Good. I'll double-check this later and maybe add a citation used in another article. Of course I assume good faith, though a more accessible citation may also aid the reader.
 * Thanks. Sandbh (talk) 04:54, 24 July 2021 (UTC)

Grateful for advice on items 4, 12. Thanks again, Sandbh (talk) 10:28, 23 July 2021 (UTC)
 * Glad to help,, and thank you for numbering the points. I am responding slowly and in pieces; some things I crossed out, and some things I left additional comments on. I also think everything would be kept neater if you replied indented (as I have here) rather than echo the list. ComplexRational (talk) 13:51, 23 July 2021 (UTC)
 * Thanks muchly ComplexRational. Elsewhere it has been written that indented replies are considered to be less than civil. Never mind. When in Rome… Sandbh (talk) 04:54, 24 July 2021 (UTC)

Review and more comments to follow. ComplexRational (talk) 15:55, 8 August 2021 (UTC)

PR second round
I'm splitting this into a new section to keep the page more comfortably readable and editable. Again, these are in no particular order and not necessarily exhaustive, though I'll try to follow the order of the article. I'll number the comments again (starting from 1); for cohesion, let's use standard indentation practices as above.
 * Thank you, ComplexRational. Timely and valuable feedback. Sandbh (talk) 09:40, 11 August 2021 (UTC)

ComplexRational (talk) 15:31, 9 August 2021 (UTC)
 * 1) section Abundance – do the two citations (Ostriker & Steinhardt 2001, pp. 46‒53 and Nelson 1987, p. 732) respectively source their entire paragraphs? If not, a separate citation for each statistic is needed.
 * Done. O & S only deal with the last two sentences. That H and He make up ca. 99% of the universe has a citation in the lede, now duplicated here. Nelson sketches the big picture, but misses some details which are covered by PA Cox, now added. Sandbh (talk) 08:24, 11 August 2021 (UTC)
 * 1)  – good, though this should not be less detailed than the lead. I'd recommend a swap with the similar statement there and that the citation (MacKay, MacKay & Henderson 2002, p. 200) is included here.
 * Done. Sandbh (talk) 09:40, 11 August 2021 (UTC)
 * Looks good. I'll leave it up to you whether you want to keep an exact duplication or remove the detail from the lead (keeping with summary style), though I prefer the latter. ComplexRational (talk) 21:57, 11 August 2021 (UTC)
 * OK. I trimmed some detail from the lead. Sandbh (talk) 23:46, 11 August 2021 (UTC)
 * 1)  – I think you mean, they occur naturally as free elements? This seems to follow the logic of this paragraph, though I suggest making it clear because it can incorrectly (though plausibly) imply that the other nonmetals don't occur naturally at all.
 * Done. Changed to "native forms". Sandbh (talk) 09:40, 11 August 2021 (UTC)
 * Good to know this meant what I thought. I don't think you actually changed it yet; the sentence still reads as it did before. ComplexRational (talk) 14:56, 11 August 2021 (UTC)
 * Update: I tried making the change myself. Feel free to tweak it as you please. ComplexRational (talk) 21:57, 11 August 2021 (UTC)
 * Looks good. Sandbh (talk) 23:46, 11 August 2021 (UTC)
 * 1)  – here and throughout the article, the element names should be written out. This appears to follow the expectation of "well-written", and this is common practice in other FAs about elements.
 * Done. Sandbh (talk) 11:54, 11 August 2021 (UTC)
 * 1)  – are there commonly known exceptions worth mentioning?
 * Comment. The next sentence gives the exception. Sandbh (talk)
 * Makes sense. I would recommend introducing it as an exception or the exception (whichever is appropriate), in order to make this clearer. To name another unwritten rule—something I remember also from the Hs FAC—clarifying this would strengthen impression of "complete" and "well-researched" because it would answer a natural follow-up question with a pertinent detail. ComplexRational (talk) 21:57, 11 August 2021 (UTC)
 * Done Copy edited to this end. Sandbh (talk) 23:46, 11 August 2021 (UTC)
 * 1) section Abundance – more inline citations needed.
 * Done. Sandbh (talk)
 * Abundance and occurrence look better now. Extraction still seems under-sourced, though. Also, page 428 of Emsley 2011 (Nature's Building Blocks) is about promethium, which has nothing to do with nonmetal extraction, perhaps you meant a different page (or page range)?ComplexRational (talk) 21:57, 11 August 2021 (UTC)
 * Done. Changed to "passim". I see no need for more sourcing given Emsley covers all the extraction data. Sandbh (talk) 23:46, 11 August 2021 (UTC)
 * That's good enough for a temporary fix (verifiability is satisfied), though I'm going to search for a more concise source so that it can be verified quickly and precisely at FAC. ComplexRational (talk) 15:23, 13 August 2021 (UTC)
 * 1)  – this can be elaborated some more. For instance, it might be worth saying that they are generally rare in the atmosphere; some He and Ar are radiogenic; and Rn exists only in traces from the decay of Th and U. As usual, whatever you choose to add, be sure to include the appropriate citation(s). Actually, this comment is applicable to the whole section, in that the occurrence of other elements can also be described in more detail. A few sentences should be more than enough, as some other aspects can be touched on in the following section (Extraction).
 * Comment. The abundance of the noble gases and the rest of the nonmetals is addressed in the previous subsection. I’ll add a citation or two to this subsection. Sandbh (talk) 09:40, 11 August 2021 (UTC)
 * Done. Sandbh (talk) 11:29, 11 August 2021 (UTC)
 * Citations now are satisfactory in this subsection. See my comment above for the following subsection. ComplexRational (talk) 15:23, 13 August 2021 (UTC)
 * 1)  – including this is inappropriate because the rest of the article does not classify At with the nonmetals. The only previous mention (section Nonmetal halogens) explicitly says At (and Ts) are expected to have metallic properties.
 * Done. Sandbh (talk)
 * 1)  – what is "unremarkable"? Unless this term is widely used in the literature, it seems opinionated.
 * Comment: Unremarkable means not worth saying anything about, give their relatively low costs compared to the specifically mentioned nonmetals. Sandbh (talk) 08:29, 11 August 2021 (UTC)
 * The rewritten sentence explains it much better, and I like the inclusion of examples. ComplexRational (talk) 15:23, 13 August 2021 (UTC)
 * 1) source Chemicool Periodic Table – the prices are on linked pages for each element, not the main PT page. It might be better to use a source that directly lists the prices (text or tabulated) and makes a clear statement implying the elements in question have cheaper unit prices in bulk.
 * Comment: There's no such unified source I'm aware of. Chemicool gives prices for gram quantities as well as bulk. The price differences are stark. Sandbh (talk) 08:29, 11 August 2021 (UTC)
 * Good to know. As with the other subsection, I'll look to see if I find anything. ComplexRational (talk) 15:23, 13 August 2021 (UTC)
 * 1) In the table, row Biological interactions (human life): I would not recommend saying, e.g., . Percentages don't mean as much when the sets of elements are so small (2/6 or similar); I would instead say "two metalloids, boron and silicon, are essential...". I'm undecided about the percentage for metals, as the set is somewhat larger and there are more than a handful of biologically essential metals.
 * Comment. Yes, 33% doesn't mean much by itself. I included %'s across all five columns to provide context. Thus: metals 17%; metalloids 33%; unclassified nonmetals 100%; nonmetal halogens 75%; noble gases 0%. I'll see about adding a [further] note on the CHONPS to give more insight into the 100% figure. Sandbh (talk) 03:32, 14 August 2021 (UTC)
 * Done. Sandbh (talk) 03:32, 14 August 2021 (UTC)
 * I'm still not really satisfied with this use of percentages. Adding them for context is helpful, yes, but I've never seen sets of elements or of so few members described with percentages in a meaningful way. We also have to consider how different sources treat metalloids; even though the set within this article is consistent, if we include Po and/or At (for example) the percentage drops to 29% (2/7) or 25% (2/8), which could lead to rather different interpretations. At least for unclassified nonmetals, it would suffice to just say "all are essential". what do you think?
 * Comment. I've amended the entry for metalloids to say, "33% (two of six) are essential (B, Si) trace elements[n 31][142]". The "two of six" picks up on your earlier suggestion. Hypothetically including At or Po and having the % drop to 29 or 25% would not make a significant difference i.e. the two % figures would remain > than metals at 17% and < less than the unclassified metals at 100%. Sandbh (talk) 11:41, 15 August 2021 (UTC)
 * 1)  – If I remember correctly, B and Si are only essential in very small quantities for plants and microorganisms but not necessarily humans. Because this sharply contrasts with CHNOPS, I would suggest highlighting this distinction in a footnote.
 * Comment. B and Si are shown as being regarded as being essential for humans, here, which is the clearest summary I've seen on essential elements. I'll add a citation.
 * Done. Sandbh (talk) 03:32, 14 August 2021 (UTC)
 * The source you linked is pretty clear on this. I also looked at the silicon article for reference, and it says (with its citations) that Si is usually considered essential, but does not assert this definitively: "there is some evidence", "difficult to prove its essentiality", etc. I'm not entirely sure what to make of this, though I think adding a mention of these less certain statements (if accurate) in the footnote would be helpful (similar to how you explain B). ComplexRational (talk) 01:31, 15 August 2021 (UTC)
 * Comment. In support of Si as an essential element, the silicon article does say, "Silicon is needed for synthesis of elastin and collagen, of which the aorta contains the greatest quantity in the human body", citing . This 2015 article, "Silicon as versatile player in plant and human biology: Overlooked and poorly understood" summarises several studies speaking to the essentiality of silicon. The latter article says, "Prolonged intake of diets low in silica causes skull and bone disabilities in humans (Carlisle, 1981)." Carlisle has 288 citations, none are refutations, judging from Google Scholar. I've added a citation for the overlooked and poorly understood article. Sandbh (talk) 04:22, 15 August 2021 (UTC)
 * 1)  – in large quantities, yes, but to an uninformed reader, it would seem to contradict the notion of these elements being essential. Maybe mention this in a footnote as well.
 * Comment. I'd intended for the "potentially "qualifier to address this. I'll add a note; it's certainly covered by Emsley, so that'll be easy to do. Sandbh (talk) 01:55, 14 August 2021 (UTC)
 * Done. Sandbh (talk) 03:32, 14 August 2021 (UTC)
 * Footnote looks good. ComplexRational (talk) 01:31, 15 August 2021 (UTC)
 * I added points 11 to 13 on a quick glance at the table and might add more later. I'll try to finish I finished responding to the rest as well. ComplexRational (talk) 14:07, 13 August 2021 (UTC)
 * Thank you! Sandbh (talk) 03:32, 14 August 2021 (UTC)
 * Responded to points 11–13, probably won't have time until late tomorrow (EDT) to continue adding comments. ComplexRational (talk) 01:31, 15 August 2021 (UTC)
 * Re your comment below, posting here to keep all my comments in my section. I'll give the article a full read-through most likely sometime tomorrow, complete my responses, and add any extra comments. Also, I'll review the closed FAC to see if any outstanding issues from there are still present. Feel free to do any remaining copy-editing for grammar, ENGVAR, and citation formatting; I can take another look at that when you're finished. Once this review is completed and closed, FAC2 should have a much better chance of succeeding. ComplexRational (talk) 02:09, 16 August 2021 (UTC)
 * I've probably finished with copy-editing for grammar, ENGVAR, and citation formatting, unless I missed something in the margins. Sandbh (talk) 00:19, 18 August 2021 (UTC)

PR second round: The sequel
I just scanned the article top-to-bottom and made a few small copy-edits. The article is in much better shape now than it was at FAC1, and I don't see any outstanding major issues. There are a few other (small) things I'd like to note: All done now. Sandbh (talk) 13:57, 22 August 2021 (UTC)
 * 1) There are two unaddressed citation needed tags (I did not add those).
 * Done. Sandbh (talk) 08:31, 21 August 2021 (UTC)
 * 1) YBG left an HTML comment re one of the endnotes, ; I haven't followed that thread (if there was one), so feel free to take another look.
 * Comment. The endnote works well so I’ve removed the HTML comment. Sandbh (talk) 11:05, 21 August 2021 (UTC)
 * 1) Grammar looks good overall, though spellings are still not consistent within one ENGVAR (in prose, there are both recognize and recognise as well as both behavior and behaviour). These need to be fixed, and the ENGVAR should then be tagged in the lead (following MOS:LEAD).
 * Fixed. Spellings corrected. For an article written in US English, since wp.en is hosted in the US, there is no requirement to tag the ENGVAR in the lead, that I could see, or am aware of. Sandbh (talk) 02:47, 22 August 2021 (UTC)
 * I don't think it's relevant that en.wp is based in the US, otherwise even articles on topics with strong ties to the UK would be written in en-US. I added the tag just so it's unambiguous for future editors and FAC reviewers. ComplexRational (talk) 15:36, 22 August 2021 (UTC)
 * 1)  – this feels out of place at the end of a subsection or immediately preceding a heading. I'm unsure what the best fix for this is; the two ideas I had were integrating this into the prose as the final sentence or converting it into a hatnote with a lead-in such as "This article describes one subclass arrangement".
 * Done. Changed to a hatnote. Top suggestion. Sandbh (talk) 11:39, 21 August 2021 (UTC)
 * 1) I re-formatted a few more chemical symbols and formulas along the lines of my earlier comment, though if I accidentally changed text that was meant to be copied verbatim (e.g. a quotation), feel free to undo my changes there.
 * Checked. Looks good. Sandbh (talk) 11:10, 21 August 2021 (UTC)
 * If it's good for you, it's good for me. ComplexRational (talk) 15:36, 22 August 2021 (UTC)
 * 1)  – does ref 176 source only the statement in parentheses or the whole sentence? In the former case, another citation is needed at the end, and in the latter case, the citation should be moved to the end.
 * Fixed. Sandbh (talk) 12:24, 21 August 2021 (UTC)
 * 1)  – same as above regarding ref 180.
 * Done. Sandbh (talk) 05:31, 22 August 2021 (UTC)
 * 1) Does ref 188  source all the content in Occurrence § Unclassified nonmetals?
 * Yes. With one exception, now fixed. Sandbh (talk) 03:57, 22 August 2021 (UTC)
 * 1)  – citation needed, anything generic describing these applications should suffice.
 * Done. Sandbh (talk) 05:31, 22 August 2021 (UTC)
 * Better now. ComplexRational (talk) 15:36, 22 August 2021 (UTC)
 * 1) Section Discovery – can the citations in endnote 41 be specifically added inline next to the content they source? This is not strictly necessary, but this is the only occurrence of such a situation anywhere in the article. However, I would say here that Marshall 2020  should have a more specific URL; this is just a homepage.
 * Fixed. Via trimming. Sandbh (talk) 06:20, 22 August 2021 (UTC)
 * Looks good. Am I correct to assume that ref 211 [Labinger 2019, pp. 303–328 (305)] sources the whole endnote? ComplexRational (talk) 15:36, 22 August 2021 (UTC)
 * Nearly there now. I added one citation needed tag where an inline citation was still missing. Also, I'm assuming that ref 179 [Piro et al. 2006, pp. 1276‒1279] source the whole statement about P; is that correct? Just have a look at these two things, and I think we're good to go. Feel free to ask a second (or third) opinion, though, if you'd like.
 * Done. Both items fixed. Sandbh (talk) 03:34, 23 August 2021 (UTC)
 * OT I'm not (yet) sure how much time I can guarantee to participate at the FAC, but feel free to ping or email me for anything specific. ComplexRational (talk) 15:36, 22 August 2021 (UTC)

Once these comments are addressed and following another check for grammar and MOS, I'd say we're nearly ready for FAC2. ComplexRational (talk) 02:02, 18 August 2021 (UTC)
 * Excellent. Your help has been invaluable and an eye-opener. Much grist for my mill, as to FAC requirements. Sandbh (talk) 03:34, 23 August 2021 (UTC)
 * Glad to help, . I haven't read everything below word for word, though 213.24.127.60's comments look very reasonable (I admit to not having considered some of their points) so I'll let you work through those and do one final check for grammar and MOS once that's done. Otherwise, that's basically it for my feedback. Cheers, ComplexRational (talk) 03:11, 24 August 2021 (UTC)

Double sharp
Just some small comments when I can see any. :)
 * Thank you! Sandbh (talk) 08:21, 13 August 2021 (UTC)

Comparison, Physical:


 * Diatomic for O – depends on the allotrope; O3 is pretty familiar
 * Done. There's now a relevant hat note. Sandbh (talk) 08:21, 13 August 2021 (UTC)


 * Pretty sure Hg is one of the most volatile metals, not the least
 * Done. Indeed. Sandbh (talk) 08:21, 13 August 2021 (UTC)


 * Crystal structure: should probably note that it is for the solid phase, in cases like helium
 * Done. Note added.


 * Not sure what the relevance of the SF6 pic is when you're mostly talking about the elements here
 * Comment. Sandbh (talk) 08:21, 13 August 2021 (UTC)
 * Done. Image moved to applications section. Sandbh (talk) 01:26, 15 August 2021 (UTC)

Comparison, Chemical:
 * Maybe something should be said about what exactly "metallic" chemical behaviour means? (Can't see rhenium as being that "metallic" in the high-school sense)
 * Done. Note added (Parish). Sandbh (talk) 08:21, 13 August 2021 (UTC)


 * Should probably say Pauling electronegativity (other scales differ; e.g. under Allen scale, P is more electronegative than noble metals)
 * Done. Note added. Sandbh (talk) 11:31, 13 August 2021 (UTC)

Double sharp (talk) 05:17, 13 August 2021 (UTC)
 * Ionization energies for Ds, Rg, Cn are not known, they are predictions
 * Done. Note added. Sandbh (talk) 08:21, 13 August 2021 (UTC)

Thanks for the quick response!

Now some I missed on the first read-through of those sections, and a few for other sections.

Comparison, Physical:
 * "In 2014, bromine was found to be an essential trace element in all animals." – but in "Comparison, Chemical", under "Biological interactions (human life)", you say that only F, Cl, I are essential among halogens? Dietary mineral suggests that this status of Br is not fully accepted yet, looking at the colour-coding. Maybe some note is needed given that this study is recent.
 * Done: Yes, that occurred as a misreading. I've added the qualifiers, "major" and "trace" so as to be able to discern further nuances. The Br citation has been cited 240 times without refutation so it'll probably pass muster. This row of the table has also been generally updated, inc. new citations. Found some very good refs along the way. Sandbh (talk) 05:44, 14 August 2021 (UTC)
 * PS: Nice open access article: The elements of life and medicines. Sandbh (talk) 05:47, 14 August 2021 (UTC)


 * Think it should just be "most heavier metals" – nobles like Pt and Au aren't really toxic for obvious reasons
 * Done: Good. Sandbh (talk) 05:44, 14 August 2021 (UTC)


 * Since you mention Bi as a physical semimetal, why not state which of the metalloids (As, Sb) and nonmetals (C) count under that too? You already single out iodine after all.
 * Done: Ditto. Sandbh (talk) 05:44, 14 August 2021 (UTC)

Now from the start:

Definition and applicable elements:
 * I like your note referencing Parish, but doesn't it make more sense to have it here first? Since this is the first time in the body (and quite early) that you mention those metallic properties that nonmetals lack.
 * Comment. Could be tricky since Parish only refers to chemical properties whereas this section refers to a preponderance of metallic properties, rather than chemical properties alone. Sandbh (talk) 07:16, 14 August 2021 (UTC)
 * Done. Moved the note and added examples of metallic props; nuanced the mention of metalloids. Sandbh (talk) 01:23, 15 August 2021 (UTC)


 * You use "four of" for groups 15 and 16 which each contribute four elements (periods 2 to 5), but instead "most of" for group 17; would prefer to make it the same.
 * Done. Very good. Sandbh (talk) 07:16, 14 August 2021 (UTC)


 * Any reason why you don't list the group 18 nobles? Since you list everyone else in this roll-call.
 * Done. Sandbh (talk) 07:16, 14 August 2021 (UTC)


 * Your pictures don't show a halogen, whereas under "Physical" there are a lot of halogens. Maybe a balance would be better, so that each major class is represented about equally? And I miss a picture of a noble gas. I suggest File:Argon ice 1.jpg, since the gaseous form is indeed pretty boring. :)
 * Done. The images now appear in order of Z. Sandbh (talk) 07:16, 14 August 2021 (UTC)

Properties:
 * "nearly all nonmetals..." well yes, but nearly all is not really impressive when you list so many possibilities? Only Br and I are left out and they're not so far (they're diatomic but not gases). I feel like there must be a way to cover everybody in such a case, maybe by "Nonmetals either exist as discrete molecular substances (often gaseous), or as polyatomic solids with open-packed forms; they usually have small atomic radii". Or something similar.
 * Done. Sandbh (talk) 07:14, 14 August 2021 (UTC)
 * I see you changed it to my original suggestion. Unfortunately, as I later realised, it's not quite right (bromine and iodine), hence why I changed it. Sorry, my bad. :( Could we look at this again? I think what I have above now should work. Double sharp (talk) 07:58, 14 August 2021 (UTC)
 * Done. This is harder to get right than it appears. It now reads: "Physically, nonmetals in their most stable forms exist either as polyatomic solids (carbon, for example) with open-packed forms; diatomic molecules (such as bromine); or as monatomic substances (such as neon). They usually have small atomic radii." Ce if you like. I added a note about ozone being polyatomic. Sandbh (talk) 01:00, 15 August 2021 (UTC)


 * "If solid..." – I admit this confused me, because I started thinking about stuff like solid nitrogen or solid argon, before I realised what you meant. So maybe you should make it clear earlier that you think about those solid at STP?
 * Done. Sandbh (talk) 07:14, 14 August 2021 (UTC)


 * Could you explain where these metal-nonmetal differences come from (courtesy of metallic vs covalent/van der Waals)?
 * Comment. Probably the explanation for the Goldhammer-Herzfeld metallicity ratio is relevant here. Sandbh (talk) 07:12, 14 August 2021 (UTC)
 * Done. Excellent suggestion. Sandbh (talk) 02:34, 15 August 2021 (UTC)

Subclasses:
 * Why not put metalloids at the end, when you list the categories in your first few classes? You're going from right to left with the exception of putting them up front. And it makes some sense because not everyone thinks they are nonmetals, although they behave similarly.
 * Comment. Sandbh (talk) 07:12, 14 August 2021 (UTC)
 * Comment. The practice has been to go from left to right: (Metals)-metalloids-unclassified nonmetals-halogen nonmetals-noble gases. The lede sentence of the paragraph has now been turned into a hatnote, thus: "While classification practices for the metalloids vary they are included here to facilitate comparison with the nonmetals." The accomodation of the metalloids is mentioned twice previously in the article. I hope that'll suffice. Sandbh (talk) 02:43, 15 August 2021 (UTC)
 * Comment. Haven't go this right yet. Sandbh (talk) 12:39, 15 August 2021 (UTC)
 * Done. New lede + ce. Sandbh (talk) 13:12, 15 August 2021 (UTC)


 * It's good to say that the metallic character is stronger for those near the line, but couldn't this have been in the Properties section where you contrast metals and nonmetals? And you could then mention that some metals also have significant nonmetallic character as the other side of the coin (e.g. bismuth is basically the weakest metal already, polonium and astatine are even happy to form aqua anions).
 * Comment. Sandbh (talk) 07:12, 14 August 2021 (UTC)
 * Done. Note added to the end of the lede paragraph in the Subclasses section. Sandbh (talk) 06:51, 15 August 2021 (UTC)


 * I am a bit uncomfortable with how many words are devoted to Og, compared to what At and Ts get. But admittedly I can't see how to cut it down without losing information, since predictions are still a bit split. That said, if you're going to talk about relativistic effects, why not tie this into the other prediction that Cn is a nonmetallic "noble liquid", rather than an eka-mercury? Of course it should probably all have the disclaimer that bulk properties are unknown.
 * Comment. Good suggestion; I hadn't thought about Cn as a nonmetallic element. Sandbh (talk) 07:12, 14 August 2021 (UTC)
 * Done. Note added to the end of the "Definition and applicable elements" section. Sandbh (talk) 06:06, 15 August 2021 (UTC)

Comparisons, Chemical:
 * I kind of want to see a comparison of acidity of oxides, since that's mentioned under Properties.
 * Comment. Should be doable. Sandbh (talk) 07:12, 14 August 2021 (UTC)
 * Already there. In the oxides row. Sandbh (talk) 01:00, 15 August 2021 (UTC)
 * I had hoped for something a bit more quantitative, or at least calling out the really strongly acidic ones (e.g. N2O5, SO3, Cl2O7, ...). :) Double sharp (talk) 08:39, 20 August 2021 (UTC)
 * Done. The strong acids have been called out. Sandbh (talk) 13:53, 22 August 2021 (UTC)

Allotropes:
 * Maybe split into more paragraphs?
 * Done. I've turned the paragraph into a list, since lists are ideal for this situation. Let's see if there any complaints at FAC. Sandbh (talk) 07:12, 14 August 2021 (UTC)


 * Maybe mention that everybody should metallise under enough pressure (see metallization pressure).
 * Already there. Sandbh (talk) 07:12, 14 August 2021 (UTC)
 * So it is, sorry. Was a bit short, so I didn't notice. :) Double sharp (talk) 08:39, 20 August 2021 (UTC)

Abundance, occurrence, and extraction
 * Maybe mention universal abundances beyond H and He? Oxygen is a respectable 1% in our galaxy. C, Ne, and N are with Fe at around or over one permille. Si and S aren't too shabby either.
 * Done. Added mention of O being the next abundant in the universe, at 0.1%. Sandbh (talk) 07:12, 14 August 2021 (UTC)


 * Native elements are cool, but mostly they appear in minerals, right? Could we have some explication of where the nonmetals often occur? (I know you mention some in extraction but maybe it could be fleshed out a bit more.)
 * Comment. Sandbh (talk) 07:12, 14 August 2021 (UTC)
 * Done. Sandbh (talk) 01:00, 15 August 2021 (UTC)

Discovery:
 * I get that it's a timestamp, but why is the freezing of Hg used? The connexion to the nonmetals is not too obvious.
 * Done: Hg removed. Sandbh (talk) 07:12, 14 August 2021 (UTC)

Double sharp (talk) 14:23, 13 August 2021 (UTC)


 * All done now. Sandbh (talk) 13:59, 22 August 2021 (UTC)
 * Looks great to me now, thanks! Double sharp (talk) 15:12, 22 August 2021 (UTC)
 * Many thanks Double sharp for you astute observations, as usual. Sandbh (talk) 03:37, 23 August 2021 (UTC)

Sandbh
At this point I believe/hope the only remaining issues are to check for orphaned cites, and to use ref names for identical cites. Sandbh (talk) 01:45, 16 August 2021 (UTC)
 * Done. Sandbh (talk) 07:52, 16 August 2021 (UTC)

IP 213.24.133.229 - Two ideas to consider
There are two general comments that I want to make and that I would definitely take on myself if I were the one to attempt to bring the article to the FAC status. I'd like to note that the article was engaging, and it reads as a piece of absolutely professional writing. I liked the section "Origin and use of the term" in particular. However, there are two important considerations that hold me from approving the article just yet (I also have a few smaller comments, but they are besides the point right now).
 * Sandbh comment: Thank you for taking the time to post your thoughts; your perception of the standard of writing; and your assessment of the article as a potentially strong FA candidate. Much appreciated, and unexpected (in a good way). Sandbh (talk) 00:47, 24 August 2021 (UTC)

What is it that makes "nonmetals" nonmetals?
First, I am surprised by how the general discussion of what makes nonmetals nonmetals is lacking in its entirety. I am even more surprised to see that nobody else has pointed this out; am I missing something? The basics of this are taught in schools. The story of how a nucleus wants to have a complete octet of valence electrons around it, how atoms get smaller as you move across a period from left to right, how less and less likely they are to give up electrons, hence the nonmetallicity, is common, why not mention this?

This content is absolutely required and I'd even expect it to have a section of its own, or at least to basically take over a different section.


 * Sandbh comment: In the article, mention is made of why the differences between metals and nonmetals arise, in the last paragraph of the Properties section. But I do appreciate your point and it is something I'll look at further. Sandbh (talk) 08:15, 23 August 2021 (UTC)
 * Done. Paragraph added to the Properties section. Some nuancing may follow. Sandbh (talk) 05:56, 24 August 2021 (UTC)

On this topic, I'm also surprised that the very important notion of negative oxidation states is not mentioned in the text as far as I can see, and is only briefly mentioned in the table, which most people are, frankly, likely to scroll through.


 * Done. Now mentioned in lede and in new table of other chemical properties in the Properties section. Sandbh (talk) 08:15, 23 August 2021 (UTC)

Categoricality of divisions

 * ''This section prompted a multi-part response by Sandbh, denoted by (a), (b), (c) etc.

Second, I am taken aback by how categorical the division in the article is. While I do know your preference for the metalloid-other nonmetals-halogen nonmetals-noble gases tetrachotomy, I maintain that the said categorization is not appropriate to be used in Wikipedia of all places right now due to the specifics of the very nature of this particular encyclopedia. I'd like to point at WP:DUE and ask you to read it not in a way in which you would seek affirmation of your presentation, but rather to read it in a way to understand the spirit of the policy, so to speak.


 * Sandbh comment (a): It is the literature that popularly counts nonmetals as either metalloids; halogens; or noble gases (not me). The consequence is that there is s a remnant of "leftover" nonmetals i.e. H, C, N, O, P, S and Se. In the literature, the nonmetals in this part of the periodic table have been referred to using over a dozen different labels, including "other nonmetals", none of which have gained traction. For that reason, after consulting with wp colleagues, I have referred to them as unclassified nonmetals. Sandbh (talk) 08:15, 23 August 2021 (UTC)


 * You are correct about how the categories of metalloids, halogens, and noble gases are common. I would particularly like to note that we are talking about "halogens," not "halogen nonmetals," as the article currently does; that term is unknown. If you're going to invent a new category like "halogen nonmetal," why not also invent the category of "chalcogen nonmetal," given that "chalcogen" is comparable to "metalloid" in terms of popularity?
 * On this note, the term "noble gases," as defined by IUPAC, includes oganesson (according to periodic table), even though IUPAC does not claim that Og is a nonmetal. Should He though Rn be called "noble gas nonmetals," too?--213.24.133.229 (talk) 17:44, 23 August 2021 (UTC)

Hints of a bigger issue

 * This hints at a bigger issue: there is absolutely no imperative that the article use a scheme in which any element must belong to a category, the set of which must also be mutually exclusive, hence there is no need for a leftover category. There is also no need to artificially exclude astatine for the halogens because it's not nonmetallic enough. In fact, it's going to be fine if some categories end up overlapping. This will rather mark that the article does a fair job at describing the existing categories, thus presenting richer encyclopedical knowledge rather than creating new basically unheard of categories: that is the job for primary sources, not an encyclopedia.--213.24.133.229 (talk) 17:31, 23 August 2021 (UTC)


 * Sandbh comment (b): The article does not use the term, "halogen nonmetals" as claimed. Rather it uses the (descriptive) phrase "nonmetal halogens." I'd previously discussed how to refer to the set F–I with wp colleagues, none of whom were enamoured with "halogen nonmetals", hence "nonmetal halogens". (Curiously, a search of Google Books and Scholar does turn up some hits for "halogen nonmetal/s".)


 * IUPAC has approved "noble gases" as a collective name for He-Rn only: see their 2005 Red Book, p. 51. Og is thus excluded. IMO, group 18 could still be referred to as noble gases, even with Og as a metallic looking reactive semiconducting solid. For example, no one quibbles that among the group 15 pnictogens N is the only asphyxiant.
 * This is indeed true, but the 2005 Red Book predates the IUPAC recognition of Og's synthesis. When IUPAC decided in 2016 that actually, new elements in groups 17 and 18 should have "-ine" and "-on" suffixes after all (overturning the 2002 decision in which they get "-ium" like any other element), they clearly use the term in a way that implies "halogen" and "noble gas" extend to 117 and 118 (currently Ts and Og): At the time of writing the previous recommendation (years before 2002), it was apparently not anticipated that the pace of discoveries of new heavy elements would soon lead to new elements of the halogen and the noble gas groups (my emphasis). Double sharp (talk) 07:13, 29 August 2021 (UTC)
 * The article twice makes clear that the subclasses are not carved in stone. For example, the lede notes:


 * "The distinction between nonmetal subclasses is not absolute. Boundary overlaps, including with the metalloids, occur as outlying elements among each nonmetal subclass show or begin to show less-distinct, hybrid-like, or atypical properties.


 * IP editor: Hints of a bigger issue?
 * I submit the article ought to do a reasonable job of, among other things, summarising the literature when it comes to the descriptive chemistry of the nonmetals. It should at least cover the common classes, as you referred to them, of nonmetallic elements. By default, this will result in some leftover nonmetallic elements.


 * Astatine: When discovered in 1940 it was considered by its discoverers to be a metal.


 * Subsequently, Hermann, Hoffmann, and Ashcroft (2013) predicted it would be an fcc metal, once all relativistic effects are taken into account. They've since been cited 38 times, without dissent.


 * Nearly everything in between those two benchmarks has been (unreliable) guesswork, with nearly all text book authors not bothering to do their homework given the minuscule number of people who actually get to work with astatine.


 * One reasonable study was by Batsanov (1972) who calculated At would have a band gap of 0.7 eV. Now, he was off the mark but added credence to the work of HHH (who did not cite Batsanov), with these three authors further predicting a band gap of 0.68 eV if not all relativistic effects were taken into account. Edwards and Sienko (1983) speculated that, on the basis of the Goldhammer−Herzfeld criterion for metallicity, At was probably a metalloid. But the G-H ratio doesn't take into account relativistic effects which, in the case of Po, result in it being a metal. Siekierski and Burgess (2002, p. 122) presumed At would be a metal in the context of some of the properties of iodine. Restrepo et al. (2006) reported that At appeared to share more in common with Po (a metal) than it did with the established halogens, thereby confirming a 1940 observation that At behaved chemically like Po, "The chemical properties of the unknown substance are very close to those of polonium." Restrepo et al did so on the basis of detailed comparative studies of the known and interpolated properties of 72 elements.


 * Sandbh comment (d): I'll look again at the article to see if there is further scope to address and clarify the topic of overlapping (or not) classes and the approach taken, including the treatment of At.
 * Partly done. Footnote added about At, at the end of the Nonmetal halogens section.
 * Done. A note has been added about At, Ts, and Og to the lede image. The note has been expanded tp explain the dashed line around the metalloids. The remainder of the article refers three times to: boundary overlaps; that some variation may be encountered among authors as to which elements are regarded as nonmetals; and that, as with classification schemes generally, there is some variation and overlapping of properties within and across each subclass. The text posted here about the history of At, and Dupasquier'scheme, has been incorporated into footnotes. At, Ts and Og are further mentioned in the Subclasses section. The content about the Nature article survey 3,300,000 abstracts has been added as a footnote.Sandbh (talk) 07:39, 25 August 2021 (UTC)


 * IP editor: Thanks for a detailed response. Let's break it down.
 * 1. There are three sets of elements used in the article that well-established: metalloids, halogens, and noble gases. That much is certain.
 * Does it mean that there needs be a fourth set for the rest of the elements? The answer to that, as far as Wikipedia is concerned, is clear: no, such need is not established in the literature. You are making your own decision by introducing a fourth set rather than following the literature. That would be absolutely fine in an authored article, but this contravenes core policies of this particular encyclopedia, those being WP:OR and WP:V.


 * Sandbh comment: I feel that some history will be helpful.
 * When the wp color-coded periodic table first appeared in 2002, it was based on a consideration of the literature. The result was a color-coded PT including the following sets (1) semimetals; (2) nonmetals; (3) halogens; and (4) noble gases. This occurred many years before my time at wp. In 2003, the sets became: (1) metalloids; (2) other nonmetals; (3) halogens; and (4) noble gases. These four sets endured for ten years. From 2013 to 2018 the four sets were (1) metalloids; (2) polyatomic nonmetals; (3) diatomic nonmetals; and (4) noble gases. The PT now appearing in the lede of the periodic table article has no colored sets as members of WP:ELEM essentially decided it would be better to cover sets of elements in lower level articles.
 * My points are: (i) having four sets in the wp PT p-block has a long-standing non-controversial history; (ii) no, I am not making my own decision to introduce a fourth set rather than following the literature; (iii) when I look at the literature I find the same approach as was seen by my predecessors in 2002/3 i.e. (1) metalloids; (2) unclassified nonmetals; (3) halogens; and (4) noble gases.
 * Now, I broadly agree there's no explicit need for a 4th set of nonmetallic elements.
 * However, I can't do anything about the fact that the literature chooses to use the sets of: halogens; noble gases; and metalloids, and the result is that there is a leftover bunch or unclassified set of elements namely H, C, N, O, P, S, Se. Noting the wobbly boundaries between the metals and the halogens F, Cl, Br and I, these orphaned nonmetallic elements have been referred to in the literature using upwards of a dozen different collective names, of which the most common is probably "other nonmetals". In an article on nonmetals they need to be addressed in some way. Thus, rather than "making your own decision by introducing a fourth set rather than following the literature" I am following the literature and the example set by the 2002 founders of the color-coded WP table.


 * Or consider this recent 107 pp. article, with 73 citations:
 * "Single-atom catalysts across the Periodic Table" Kaiser et al. 2020, Chemical Reviews, vol. 120, no. 21, 11703–11809, cited by 73,.


 * The sets they use are shown in the table. Note the four sets of nonmetals.
 * Sandbh conclusion: In this light I do not accept your assertion of contraventions of WP:OR and WP:V. Sandbh (talk) 07:22, 30 August 2021 (UTC)
 * I suspect you view this rather differently from how I do it. I'll try to have crafted a picture by the end of the week to see if my point can be clearer then, as well as provide a few more comments.--213.24.135.49 (talk) 17:36, 31 August 2021 (UTC)

Lede image
I've been able to create the files I had in mind, although I'm not going to boast about their aesthetics.

I think the lead image should not be bothered with subcategories and should rather be concerned with the definition of the concept of nonmetals. In the first picture, I have provided three definitions: nonmetals excluding metalloids, nonmetals as defined by the metal-nonmetal diving line shown in our article on this line, and nonmetals including all metalloids.

I have also provided a picture that makes it clearer that halogens and metalloids are often understood to not be subset of metalloids.

Both files feature color coding and a common border for each category. The latter is going to be useful since some categories overlap.

I will send you the source file for these pictures.--213.24.135.49 (talk) 20:27, 4 September 2021 (UTC)

In fact, I'd like to suggest these files are used instead of the ones used right now precisely for this reason: introducing the subcategories in the lead section, especially given the fuzziness of any given categorization, is sort of "too much information" at this point. You can have a picture showing these subcategories later, when you discuss them. Then will the picture be more appropriate.

Also, I must note that even the picture used right now could use some improvement: if metalloids are divided by the metal-nonmetal dividing line, then the same should be done with the halogens.

If you have trouble editing the source file, just let me know, and I'll add whatever you may require (group numbers, etc.).--213.24.135.49 (talk) 20:36, 4 September 2021 (UTC)

Also, if you want me to change the composition of the classes in these pictures, just let me know. I included astatine in the "nonmetals plus" group on the basis that it might be a metalloid, but I don't insist it should necessarily be included. You may not want to have a nonmetal category that excludes metalloids altogether, that's fine by me, too. You may also want to include Cn, Fl, and/or Og for the same reasons as At as "nonmetals plus" or you may want to remove period 7 from the pictures altogether; that is fine by me as well. Or you may want me to change the coloring scheme to your red-yellow-blue, which I would've done myself when I was making these pictures had the thought of that occurred to me. Just say a word.

The point that I'm making is that there should be a picture that only defines the nonmetals, and this picture should be used as the lead picture for the article; and there should be a separate picture for subclasses, which should be present them as not necessarily subclasses of the nonmetal set, but rather as separate groupings, and this picture should be used in the appropriate subsection. The nonmetals are hard to categorize, after all, and this is well reflected in the picture I'm proposing. Specific details beyond that is not something I want to argue about, and I'll gladly go along with any request.--213.24.135.49 (talk) 09:53, 5 September 2021 (UTC)
 * Sandbh to IP editor: I've taken on board your suggestion that the lede image should basically only show which elements are nonmetals. This is indeed a better way of doing it, thank you. The "sets of nonmetals" image is now in the subclasses section.


 * The change represents an easier way to do things, so I was able to do a fair bit of trimming. Quite a bit of copy editing was needed too, to bring the article into line. I'll need to look at the flow again, to make sure it still works. I didn't do anything with your pictures as the first thing I had to do was determine if the new approach would be better, and then how to execute it. I'll now look at them. Sandbh (talk) 08:11, 6 September 2021 (UTC)

One more thing I keep forgetting to say: as I mentioned elsewhere, I really do understand your point about how, for example, "nonmetal halogen" is merely a convenient phrase rather than a term. The problem is that it's not evident from the article that that's your intention.

Using these pictures will help to clarify this and will alleviate a great deal of other concerns I have stated on this page.--213.24.134.134 (talk) 08:18, 6 September 2021 (UTC)

I see that's about what you've done. That's very good to know, although I still suggest that showing that astatine is a halogen in the subgroupings picture is important so that the readers don't get the impression "halogen nonmetal" is a legitimate term, which is not your intention, according to what you stated on this page. (This is the impression I actually get from seeing how the article is today even if you don't want to create it.)

I will revisit my other comments and your responses to them later this week. In the meantime, why does the metal-nonmetal dividing line in the lead picture go the way it does? I would normally want to group B, Si, As, and Te with other nonmetals.--213.24.134.134 (talk) 08:30, 6 September 2021 (UTC)
 * Sandbh to IP editor: I hope you'll be happy with the lede image now, which combines your suggestion with the original lede image. The latter has been moved to the "Definition and applicable elements" section. The updated caption to the lede image refers to At as a halogen. Sandbh (talk) 03:50, 8 September 2021 (UTC)
 * I'm not happy with the lead image as it stands just yet. One of the previous images, namely this one, did a better job, even if it still attracted comments from me. The categorization you present is excessive at this point, and it does not serve a useful purpose yet (whether there is a purpose to begin with can be discussed in the appropriate section of the article).
 * As a writer, I have learned to be concerned with what I want to tell the reader at a particular moment. I don't have to and I don't need to shower them with information just because I can. I'm better off figuring out what I should tell the reader now. The lead image is supposed to help identify the subject of your article, not go into details such as internal classification.
 * To illustrate the idea there can be too much information at a certain point, let me suggest this: there is a misconception among some people that the capital of Australia is Sydney, and Wikipedia should definitely address this misconception. If you added the correct knowledge (of course, it's Canberra) to the lead image, the article would not lose anything in terms of information, and it will help the readers by providing them some knowledge. So, should you? The answer will be a no, obviously, because when you only begin to read the article, you want to have a concept of what you're reading about, not every piece of information you can have, and any information you're not looking for will create a distraction. It is precisely for this reason why you should not have subcategories in the lead image: they are a distraction. Before you want to categorize something, you want to know what it is that you're going to categorize.
 * In fact, since the goal is to help identify the subject, you might consider that the periodic table itself is a tool of categorization and it does not provide the most basic of knowledge. What would be a much better choice, now that I think about it, is a collage of different nonmetals. This would illustrate what a nonmetal is, rather than how they can be categorized. This is what the first paragraph of the article is concerned with, too, and you'd be best off complimenting that particular paragraph. Take a look at the metal article: it does precisely that.
 * You could have a collage of brittle iodine, dull graphite, liquid bromine, and gaseous nitrogen, for example, to show your readers that nonmetals differ a lot in their appearance.--213.24.134.134 (talk) 13:24, 11 September 2021 (UTC)
 * Sandbh to IP editor. It seem to me that comparing the approach taken in the metal article with that taken in the nonmetal article doesn't work so well. The nonmetal article starts by saying, "In chemistry, a nonmetal is a chemical element that is…". In contrast, the metal article starts, "A metal…is a material that…". So the focus of the nonmetal article is on chemistry whereas for the metal article, it's a more general focus, encompassing chemistry, physics and astrophysics. Even then, there is not much chemistry in the metal article, compared to the nonmetal article.
 * Re, where you said…
 * "Before you want to categorize something, you want to know what it is that you're going to categorize."
 * …that is how the lede is structured. The lede paragraph of the lede explains what a nonmetal is. The third paragraph of the lede then summarises different sets of nonmetals.
 * Most people understand what a metal is: shiny, conducts heat electricity, bendy (tin); tough (steel). But ask them what a nonmetal is. Having tried this myself, most have no idea. The situation is not helped by having so many different kinds of nonmetals: shiny, coloured, transparent; solid, liquid, gas, conductors, semiconductors; insulators. So, once outlining what a nonmetal is, it's good to calm things down by showing that (as per the literature) there are noble gases, halogens, and metalloids, and a set of leftovers nonmetals.
 * I'll think some more about this, including your idea of a collage. Sandbh (talk) 04:23, 12 September 2021 (UTC)
 * Sandbh to IP editor. I tried your idea of a collage, and it turned out to be brilliant! Many thanks for your continuing observations and interest in the article. Sandbh (talk) 08:18, 12 September 2021 (UTC)
 * The pleasure to help you is all mine. I'm glad that you liked the idea. I took the liberty to tidy up the collage a bit. I think you'll like that, but feel free to revert me if you want to.--213.24.126.91 (talk) 18:30, 12 September 2021 (UTC)
 * The image is so much better now! Thanks again! Sandbh (talk) 08:25, 13 September 2021 (UTC)


 * IP editor: 2. Those three sets I just mentioned, are they subsets of the nonmetal set? Again, the answer to that in a clear no. Astatine is widely recognized as a halogen, and it is also recognized to not really be a nonmetal. So it is readily clear that halogens do not form a subset of the nonmetals. To get around this, you use the term "nonmetal halogen." (Indeed, I made a mistake by confusing "nonmetal halogens" and "halogen nonmetals"; my bad.) However, while the term "halogen" is common, the term "nonmetal halogen" is really really not, being behind in popularity by as much as four orders of magnitude. This is a really obscure term, and therefore, it should not be given such prominence. The second sentence of WP:FRINGE, an official guideline, reads, "Because Wikipedia aims to summarize significant opinions with representation in proportion to their prominence, a Wikipedia article should not make a fringe theory appear more notable or more widely accepted than it is."
 * The same also goes for the metalloid class. A statement such as "germanium is a metalloid," without a doubt, represents a common view in the literature. The statement "germanium is a metalloid, and, therefore, a nonmetal" does not. However, a casual reader would undoubtedly draw the latter conclusion from the article as it stands, particularly including its lead picture. Therefore, WP:FRINGE is not adhered here.
 * (By the way, I hope this makes it even more clear why there is no need for a fourth category, since two of the three (I accept your logic on noble gases) claimed subcategories of the nonmetal class are, in fact, not subcategories.)
 * With this in mind, I suggest you rethink both the Subsection section and the lead image entirely to better comply with the policies of Wikipedia. I want to stress that your present classification is not faulty in any sense (certainly think of it as you like), but that it is not in line with Wikipedia's policies.--213.24.133.229 (talk) 20:03, 26 August 2021 (UTC)
 * Sandbh comment: I feel that the term "halogen nonmetal" for F, Cl, Br, I is no more than a convenient descriptive phrase. The subject elements are widely recognised and regarded as halogens and nonmetals. I see no fringe “theory” involvement. All the facts are set out in the literature.


 * No doubt the term "halogen nonmetal" is scarce, as is its counter part "nonmetallic halogen" since it is universally known that halogens are nonmetals (except for At and Ts). So there would not be many occasions calling for their use. That said, here are some examples dating from 1902:


 * "It will be seen that these elements of zero valence and no chemical character form a natural passage from the strongly electro-negative non-metallic halogens…"
 * — A review of some of the recent literature of the periodic law, RH Bradbury - Journal of the Franklin Institute, 1902


 * "In the decidedly nonmetallic halogen group…"
 * — Qualitative analysis as a laboratory basis for the study of… Page 64, William Conger Morgan · 1906


 * "And among the nonmetallic halogens we find the…"
 * — ''Recent Advances in Physical and Inorganic Chemistry - Page 245, Alfred Walter Stewart · 1920


 * "In a similar manner the nonmetal halogen elements are arranged"
 * — Essentials of Chemistry - Page 54, Luros G · 1955


 * "The alkali metals of Group la combine readily with the nonmetal halogens of Group VIIa."
 * — General Chemistry - Page 87, John Arrend Timm · 1966


 * "Nitrogen was the subject of Chapter 15, and the nonmetallic halogens, of Chapter 17."
 * — Introduction to Chemistry - Page 226, Williams et al. · 1973


 * "The electron configurations of atoms of some of the elements, the alkali metals and the nonmetallic halogens and noble gases, are given in Table 4-1."
 * — Geology: Our Physical Environment, Page 30, Davis et al. 1976


 * "The nonmetallic halogen atoms easily pick up an electron, thus forming halide ions."
 * — Chemistry Decoded - Page 346, Leonard W. Fine · 1976


 * "Iodine is a nonmetallic halogen, having the lowest reactivity of any substance in this group."
 * — Properties of Nonmetallic Fluid Elements - Volume 3, Part 2 - Page 115, Yeram Sarkis Touloukian, ‎Cho Yen Ho · 1981 · ‎p. 115


 * "An activity series for the nonmetallic halogens was given in Chapter 6."
 * — Understanding Chemistry - Page 386, Robert J. Ouellette · 1987


 * "Other properties are similar to those of the nonmetallic halogen elements in Group VIIA or 17 in the second column from the far right of the table…in this case, the nonmetal halogen element is reduced to its halide ion."
 * — 'Chemistry: A Basic Introduction'' - Pages 125, 271, George Tyler Miller · 1987


 * "Iodine resembles bromine because they are nonmetallic halogens that form compounds like those of chlorine."
 * — Chemistry - Page 8, Nathan · 1993, p. 8


 * "What causes gold to emulate many properties of the nonmetallic halogens?"
 * — Chemical Principles, Page 549, Steven S. Zumdahl · 1995


 * "Particular but we must not forget the novel involvement of the non-metal halogens."
 * — The Chemistry of Evolution: The Development of our Ecosystem, R.J.P Williams, ‎J.J.R Fraústo da Silva · 2005


 * "Among the other nonmetal halogens used to partially halogenate metal oxides…"
 * — Inorganic Reactions and Methods, The Formation of Bonds to…, A. P. Hagen · 2009, p. 221


 * "Non-metallic halogens such as chlorine, iodine and bromine are salt-forming elements."
 * — "TRPM7 is regulated by halides through its kinase domain", H Yu, Z Zhang, A Lis, R Penner, A Fleig - Cellular and molecular life… 2013


 * "Nonmetallic halogen element of atomic number 53…
 * — Hawley's Condensed Chemical Dictionary - Page 765, Michael D Larrañaga, ‎Richard J. Lewis, Sr., ‎Robert A. Lewis · 2016


 * "Non-metallic halogens are very attractive"
 * — "Hydrothermal preparation of visible-light-driven Br-doped Bi2WO6 photocatalyst", P Dumrongrojthanath, A Phuruangrat, S Thongtem… Materials Letters, 2017 - Elsevier


 * "…chlorine; element #17; a nonmetal halogen gas"
 * — Trauma, 8th Edition - Page 1139, Moore et al. 2017, p. 1139


 * "…and a more detailed grouping in families of: alkali Earth, alkaline Earth, transition metal, rare Earth, other metal, metalloid, and nonmetal halogen to noble gas."
 * — Illustrated Encyclopedia of Applied and Engineering Physics, Robert Splinter · 2017, p. 382


 * At no point has the article said, “germanium is a metalloid, and, therefore, a nonmetal".


 * OTOH it has been known for over 100 years that metalloids behave chemically like weak nonmetals. The article goes to quite a bit of effort to explain that metalloids are included within its coverage in light of their nonmetallic chemistry and for comparative purposes. The caption to the lede image, noting the varying treatment of the metalloids, has been updated to make this clearer. Further, the lede says the metalloids are included for comparative purposes given their nonmetallic chemistry.
 * Prompted by this discussion, I've amended the lede image so that it now show a traditional zig-zag or rough dividing line between the metals and nonmetals. The accompanying caption now immediately alerts the reader as to what's going with the metalloids. I also added a note about At, and Og.
 * Sandbh conclusion: I feel that my observations, additional explanations, and associated edits, now remediate your concerns. Sandbh (talk) 07:22, 30 August 2021 (UTC)

Clusters of nonmetals in the literature

 * Sandbh comment (e): This Nature article has a figure 1a, here, showing the proximity of names of the elements based on 3.3 million abstracts published between 1922 and 2018 in more than 1,000 journals. The overall distribution of the element names exhibits a topology reminiscent of the periodic table. Clusters for metalloids, unclassified nonmetals, nonmetal halogens, and noble gases are readily apparent.


 * I looked closely at this figure. First of all, nowhere does it mention the category of halogen nonmetals, or, in fact, halogens at all. Second, it is not readily apparent, because the author chose a to group F, Cl, Br, and I with H, N, and O. Third, I am left wondering what this graph says about the grouping of Be, and if Be is an exception, that surely the conclusion is not as universal as one might casually think, particularly since the author does not arrive at it himself. As such, I do not believe the picture supports this grouping; certainly not in the sense of WP:V.


 * Sandbh comment: It doesn't mention halogens since the categorisation scheme used is polyatomic and diatomic nonmetals; and noble gases (monatomic nonmetals nonmetals. This scheme is mentioned in List of alternative nonmetal classes, here.


 * On beryllium, the authors write:


 * It is remarkable that using only relative positions of words in scientific text the algorithm learns a high dimensional representation for elements that is very similar to the periodic table when projected onto a plane. However, not all of the structure of our t-SNE projected word embeddings match well with the periodic table. Given that this is a context-based representation, it is unsurprising that the inert noble gases are far removed from the rest of the elements whereas post-transition metals, metalloids, and alkali metals, which are often used with each other in various applications, group closer together. The astute reader may observe that hydrogen is clustered with oxygen, nitrogen, and carbon; we attribute this to the fact that these elements are the main components of organic compounds. Similarly, Radon (Rn), radium (Ra) and polonium (Po), all radioactive elements, are found in closer proximity to uranium (U) and thorium (Th) in the plot than to their neighbors in the periodic table. Some elements, nevertheless, are completely out of place compared to the periodic table for what we believe to be non-physical reasons. We note that these elements’ symbols overlap with common words that have the same spelling, such as “be” for beryllium, “at” for astatine or “Tc” for technetium which is also used to denote critical temperatures. Despite this, the high dimensionality of the embeddings enables relationships such as “being” - “Be” + “measure” ≈ “measuring” and “BeO” - “Be” + “Mg” ≈ “MgO” to be captured simultaneously, therefore, preserving both the chemical and the syntactic relationships.
 * Sandbh (talk) 04:22, 24 August 2021 (UTC)


 * I readily accept the authors' thinking on beryllium.
 * As for the categorization you suggested, there are two conclusions to draw from it:
 * 1. Contrary to your claim, clusters for metalloids, unclassified nonmetals, nonmetal halogens, and noble gases are not at all readily apparent. The noble gases cluster is apparent, but that's about it. For example, with no outside knowledge, no pre-drawn borders, no anything, it would be natural to assume that Se should end up in the same class as Sb, As, and Te. It would be even more natural to assume that B and P should end up in the same class. However, neither is the case in your classification. From this, it appears to me that the way the four clusters you mentioned are "readily apparent" seems only apparent when you want to see them to begin with.
 * 2. None of this matters anyway because you are the one making this conclusion and not the source, making it, therefore, original research, and this, again, does not sit well with Wikipedia's policies.--213.24.133.229 (talk) 20:03, 26 August 2021 (UTC)


 * Sandbh comment: Please see the stripped back image, from which I replaced the clutter with two dashed lines.


 * For a general reader looking at the original image, I agree the clusters for metalloids, unclassified nonmetals, nonmetal halogens, and noble gases are not readily apparent. However, as the authors noted, the distribution is consistent with the literature, and resembles the contours of the periodic table. Since the image is based on over 3,000,000 abstracts, I'm not surprised. Taking into account the boundary overlaps that occur in the periodic table, the image confirms the literature-based wisdom of the editors who put together the first colour categorised wp PT, nigh on twenty years ago.


 * Selenium is commonly described as a metalloid in the environmental chemistry literature. It moves through the aquatic environment similarly to arsenic and antimony; its water-soluble salts, in higher concentrations, have a similar toxicological profile to that of arsenic. Outside of environmental chemistry its occurence in lists of metalloids falls away.


 * That P and B are close together is curious. Some shared properties, and considerations, that may have something to do with this are:
 * Basics
 * Like B, black P (the most stable form) is a metallic-looking semiconductor, and has bonding or valence bands with delocalized character.
 * P's electronegativity of 2.19 is closer to the metalloid average of 2.05 than it is to the unclassified nonmetal average 2.65; that P's EN lies within the metalloid range was mentioned by Rochow (1966, p. 7) in his book "The Metalloids".


 * Compounds
 * Both form numerous compounds with a +3 oxidation state.
 * Each form a series of binary hydrides of composition BnHn+m (n an integer >1, m = 4, 6) or PnHn+2 (n = 1–9).
 * B has a high affinity for oxygen, forming borates, as does P for oxygen, forming phosphates.
 * B2O3 and P4O6 are each white, polymeric, glass-forming, acidic oxides.
 * Borophosphates form readily upon the melting of borax with phosphorus salts since B can accept an electron pair, and P can donate one; between silica and P the structural match is not so good.
 * Borides and phosphides (and silicides) display many similarities in structure and properties.
 * Interest in boron/phosphorus chemistry "exploded" in the 1980's.
 * B and P can form compounds with varying degrees of multiple B-P bonding, including cage compounds with transition metals.
 * Icosahedral fragments are found in B; structural motifs of elemental forms of P are seen in some compounds of P.


 * Alloying
 * Each of them find uses as alloying elements in iron and steel.
 * Nickel/phosphorus or boron alloys are most regarded as synonymous for the "electroless plating" of engineering components, to improve performance and life.


 * Si is presumably not so close to B, but instead closer to Ge, given Ge and Si launched the semiconductor revolution in the 1960s.


 * Conclusion: As you noted, the noble gas cluster is readily apparent. The clusters for metalloids, unclassified nonmetals, nonmetal halogens are clear. It is acknowledge in the literature that boundaries become classes can be wobbly. Case in point Se, which is regularly counted as a metalloid in the environmental literature, but not elsewhere. That P and B are close is understandable. As the authors noted, the word proximity distribution closely follows the contours of the periodic table. That is, I didn't make this conclusion about the four clusters. You have acknowledged the existence of metalloids and noble gases. What does that leave? Halogen and orphan nonmetals. Sandbh (talk) 07:22, 30 August 2021 (UTC)

Not too categorical expressions

 * Sandbh comment (f): In the article, I went to some length to use "not-too-categorical expressions" such as "three or four"; "may or may not be recognized"; "distinction between nonmetal subclasses is not absolute"; "generally counted"; "no rigorous definition"; "broadly [speaking]"; "some variation may be encountered among authors"; "this section describes one approach to subclasses of nonmetallic elements…for other perspectives, see…"; "as with classification schemes generally, there is some variation and overlapping of properties within and across each subclass…one or more of the metalloids are sometimes formally classified as nonmetals"; "classification practices for the metalloids vary"; "the dashed line around the metalloids denotes that, depending on the author, the elements involved may or may not be recognized as a distinct class or subclass of elements." Sandbh (talk) 08:15, 23 August 2021 (UTC)


 * This does not explain, however, why all these not too categorical expressions are used for this grouping and not any other one.--213.24.133.229 (talk) 17:31, 23 August 2021 (UTC)
 * Sandbh comment: In the article, the "not-too-categorical" expressions have been applied generally rather than necessarily being restricted to any one subclass. In classification science, hard cases at the boundaries are common. This is especially the case for the metalloids, hence the dashed lines around them. I'll add a note about the latter to the lede image. Sandbh (talk) 04:37, 24 August 2021 (UTC)
 * Done. Including as set out after my latest "Done", above. Sandbh (talk) 07:39, 25 August 2021 (UTC)
 * Unfortunately, you did not really answer my question. If you read this dialogue closely, I asked "why are these particular categories used as primary at all," and you answered, "I did not make them too primary." This doesn't answer what I asked.
 * If you consider the logic in the other responses I gave today, it should be apparent that the present classification is way too voluntary---I stress again---for Wikipedia rather than absolutely.--213.24.133.229 (talk) 20:03, 26 August 2021 (UTC)
 * Sandbh comment: Given there's no absolute classification in the literature, one attempts to impartially reflect what there is, fuzzy boundaries and all. You've agreed the sets of ;  ; and   are common. By default, this leaves a set of nonmetals with no widely accepted collective name. Probably the most common conception of the orphan nonmetals, in the literature, is their importance as bio(geo)chemical elements, or the atoms of life. Biologically, that covers CONPS, with little H hanging on whenever there is an electron going; and Se being included in the twenty-first amino acid of life, selenocysteine, and apparently being genetically encoded in all domains of life. (Of course, there other nonmetallic elements with biochemical roles such as Cl and I, but the orphan nonmetals are the biggies).


 * Since I don't hold a brains trust monopoly, I'm happy to consider what alternative you have in mind. Sandbh (talk) 07:22, 30 August 2021 (UTC)
 * If I may be so bold as to suggest something outside my own section: if I were writing this, I would probably simply avoid saying "unclassified nonmetal" that much. Simply because if you say it that often, it starts to sound like a category even if it's intended to be a non-category. So, where you wrote "Diagonal relationships between some of the unclassified nonmetals echo similar relationships among the metalloids", I might have written "Diagonal relationships between some of these nonmetals echo similar relationships among the metalloids". But I think the categorisation is pretty fine: the ACS and Britannica tables do something quite similar with their colour-coding. It is indeed common to single out halogens and noble gases and then be confused about what to do with the other nonmetals. Maybe the slight change I'd make is perhaps to mention some possibilities: at least, what the RSC table does seems worthy of mention. (They just continue the group scheme. After all, most pnictogens and chalcogens are nonmetals/metalloids, except the heaviest ones.) Double sharp (talk) 09:48, 2 September 2021 (UTC)
 * Sandbh to DS comment: Excellent idea. I removed some references to "unclassified nonmetals" and replaced all instances of "the unclassified nonmetals" with "unclassified nonmetals". On a related note it turns out there are several more references to "other nonmetals" in the literature, than I'd previously thought. The Subclasses section on unclassified nonmetals now includes relevant citations. EB and the RSC PT has been listed as examples. Interesting to see the RSC count metalloids as nonmetals, wheres EB split them between other metals and other nonmetals.


 * Sandbh comment (g): Further to this end, there is a hatnote in the Subclasses section, which says:
 * "This section describes one approach to subclasses of nonmetallic elements; for other perspectives, see List of alternative nonmetal classes." (Reading further down your comments, I see you mention this hatnote so I'll leave it for now.) Sandbh (talk) 08:15, 23 August 2021 (UTC)


 * Same as just above.--213.24.133.229 (talk) 17:31, 23 August 2021 (UTC)
 * Sandbh: Same as above. Sandbh (talk) 04:37, 24 August 2021 (UTC)

Just which elements are nonmetallic
The same could be said of the exact composition of the entire master class.

Here's one quotation from the article:


 * There is no rigorous definition of a nonmetal. Broadly, any element lacking a preponderance of metallic properties—such as lustre, deformability, good thermal and electrical conductivity, cationic behavior in solution, and an oxide that is soluble in acid[6]—can be regarded as a nonmetal. Since metalloids tend to lack such a preponderance, and are more closely allied to the non-metals in their chemical behavior,[7] they are here counted as such including for comparative purposes.[n 1] Some variation may be encountered among authors as to which elements are regarded as nonmetals.


 * The twenty-three elements counted as nonmetals in this article comprise...

So why does this article choose to use this particular composition? I genuinely don't see why the article does this in particular other than this being a voluntary choice of the person who wrote this. I can't find any other justification in the article. While I do recall making some editorial decisions when writing featured articles of my own, they were never, and should have never been, about something as basic as the concept in the title of the article itself---again, see WP:DUE.

The article even notes, "Steudel[9] counts 23 elements as nonmetals, including astatine but not antimony." So why was Steudel's grouping not chosen then? I see no relevant explanation in the article.


 * Sandbh comment: I wasn't aware of the passage by Stuedel until very recently. The 23 elements counted as being nonmetallic in the article are the 23 elements long regarded in wp as being either noble gases; halogens; metalloids; or leftovers. When I did read what Stuedel had written I was pleasantly surprised to see that he'd counted the same number of nonmetallic elements, with the minor difference being Sb and At. On Sb, wp has long regarded it as a metalloid. I further discussed the status of Sb with a wp colleague, at considerable length, and, based on the literature, we agreed to leave it as a metalloid. When At was discovered in 1940 it was considered by its discoverers to be a metal; the most recent (2013; 38 citations) prediction, taking into account relativistic effects, is for it to be monatomic metal, with an FCC structure. I'll add a note about Sb and At.Sandbh (talk) 08:15, 23 August 2021 (UTC)
 * Please note that I do not at all argue that Sb is not a metalloid; rather, I'd like to point out that if you ask somebody to draw a merely dividing metal-nonmetal line (which runs through the metalloid category), it is not uncommon that Sb ends up on the metal side, as was the case with my schoolbooks.--213.24.133.229 (talk) 17:31, 23 August 2021 (UTC)
 * Sandbh comment: I'll look to adding a note to this end. Sandbh (talk) 04:41, 24 August 2021 (UTC)
 * Done. Note added. Sandbh (talk) 07:45, 25 August 2021 (UTC)

It is not unheard of, for example, that Ge is counted as a metal. My schoolbooks featured periodic tables that marked Ge and Sb as metals and At as a nonmetal. Why is this opinion in particular not reflected in the lead image? Granted, my schoolbooks don't even count as sources that were published in English, but there is some variation of opinion in English-language sources just as well. It would make most sense if the lead image focused on how some elements are always counted as nonmetals and some are not always counted as such. For example, your own metalloid article does a tremendous job at precisely this. I couldn't ask you to do the same here, but I'd rather suggest a differentiation between nitrogen and oxygen (which are always counted as nonmetals) and germanium and antimony (which are not).
 * Done. As above. Sandbh (talk) 07:45, 25 August 2021 (UTC)


 * Sandbh comment: Yes, Ge was and is very occasionally still referred to as a metal. I recall it came to be referred to as a metal on account of impure samples appearing to conduct electricity as if it were. It was later realised that it was a semiconductor, which put paid to any serious notions of it being a metal. It nevertheless continued to be called a metal in some quarters out of tradition or because it fell on the metal side of the notional dividing line between metals and nonmetals. I didn't include something to this effect in the lede image as I thought the incidence of Ge (a semiconductor) being referred to in the literature as a metal was nowadays either too rare to merit inclusion or a textbook error. Along these lines, N has been referred to as a metalloid and Ge and Sb have sometimes been referred to as nonmetals.
 * Sandbh comment: I'll look further at the image in the lede to see if I can add some notes about e.g. Ge, and perhaps N and Rn as metalloids, in order reinforce the indicative nature of some of the boundaries. Sandbh (talk) 08:15, 23 August 2021 (UTC)
 * Same comment as above: when I say that Ge may be considered a metal, I merely claim that it may end up to the left of the dividing line rather than outside of the metalloid class.--213.24.133.229 (talk) 17:31, 23 August 2021 (UTC)
 * Sandbh comment: Acknowledged; stay tuned. Sandbh (talk) 04:41, 24 August 2021 (UTC)
 * Fixed Per the footnote to the lede image. Sandbh (talk) 07:45, 25 August 2021 (UTC)

Another quote:


 * Three or four kinds of nonmetallic elements can be discerned...

I'm sure that they can be discerned, but it's one thing to say they can be discerned, and it's something completely different to use this classification in the article. I reread the entire subsection on subclasses carefully if there is any justification for why these classes are used in the article other than "they can be discerned." I found nothing. A brief re-reading of WP:V has raised some concerns in me.


 * Sandbh comment: I'll seen if I can refine this passage. Perhaps, "In the literature, three or four kinds of nonmetallic elements can generally be discerned..." or something like that. Sandbh (talk) 08:15, 23 August 2021 (UTC)
 * I'd have exactly the same concerns with this phrasing as with the original one. Why in particular won't the article note that some other categories can be generally discerned instead, as suggested in List of alternative nonmetal classes?--213.24.133.229 (talk) 17:31, 23 August 2021 (UTC)
 * Sandbh comment: Good point; leave it with me. Sandbh (talk) 04:41, 24 August 2021 (UTC)
 * Fixed. Sandbh (talk) 07:45, 25 August 2021 (UTC)
 * The present wording simply does not hold true. As demonstrated in the Google Ngram above (here's one more link to it), "nonmetal halogens" is not a commonly discerned class of elements (nonmetallic or otherwise), contrary to the class of halogens, which is a commonly discerned class of elements.
 * Sandbh comment: I've addressed this in the Categorically of divisions section, including examples from the literature. Sandbh (talk) 08:06, 30 August 2021 (UTC)


 * I really do think that you're trying to hold onto a classification because you've got a certain liking to it, rather than because it is actually common in the literature, and Wikipedia favors the latter over the former.
 * Sandbh comment: I've addressed this in the Categorically of divisions where I set out the history of the wp color-coded periodic table since it first appeared in 2002. Sandbh (talk) 08:06, 30 August 2021 (UTC)
 * Please consider the following. You intend to go to FAC with this article. I've raised these concerns. You are, in my opinion, brushing them off. Do you think other people will see merit in them or will they reject them, should somebody bring my concerns to the FAC or should someone raise them independently from me? (That won't be me, to be clear on this.) How will this affect your article's chances to get a bronze star? How will the FAC coordinators react to this, how will the FAC end? Of course, it may be that my thinking is wrong instead. Please be honest with yourself on this, is it really? You really don't need to answer this explicitly (I will, in fact, appreciate it very much if you don't), but please do think about it.--213.24.133.229 (talk) 20:03, 26 August 2021 (UTC)
 * Comment Sandbh (talk) 07:34, 30 August 2021 (UTC)

Serious question, though: why not just say you're covering anything that has reasonably been called a nonmetal? I really don't think you're far off from that, and it would probably answer charges of selectivity. The exception being maybe astatine because everyone knows little and assumes it's the fifth normal halogen, and you could deal with that along the lines of "Astatine, having a very short half-life, is little-studied. Generally, it is assumed (in the absence of much work having been done on it) to follow the nonmetallic nature of its halogen congeners. There is, however, growing experimental and theoretical evidence that this might not be the case." Since it's so little studied, I suspect you do not even have to bother with it in the comparative tables at all. (I mean, you don't bother with liquid-metal almost-noble-gas copernicium and flerovium, do you?)

Of course there are a few somewhat strange inclusions into nonmetals that are sometimes used to make a point, such as tin, lead, bismuth, and polonium (included in Wulfsberg). I doubt they are common, and you could probably back that up. And you could just deal with that something like how you do the sporadic inclusions in metalloid (e.g. N, Zn, Rn), noting that the term nonmetal is sometimes cast extremely widely.

I appreciate that backing this up probably requires something like list of metalloid lists, which I understand if you're not keen on doing again. :) Double sharp (talk) 09:55, 2 September 2021 (UTC)
 * '''Comment. Sandbh (talk) 06:56, 3 September 2021 (UTC)
 * Sandbh comment: Excellent Brilliant idea. The trick will be how to phrase it without the need to compile a list of nonmetal lists, as you say. Then again, I've never seen Al, Ga, Sn, Bi counted as nonmetals. Metalloids yes, but nonmetals? Given, according to List of aqueous ions by element, all four form cations, I wouldn't get that. That table of Wulfsberg is presumably mislabeled or is missing a footnote since, elsewhere in his Principles of Descriptive Inorganic Chemistry book (1987), in which the subject table appears, he refers to Al, Sn and Bi as metal. Sandbh (talk) 07:18, 3 September 2021 (UTC)
 * Wulfsberg seems to sometimes include elements like Bi and Po in his tables when illustrating what nonmetallic elements do (another case) and sometimes not (also on that page). I don't have his 1987 book, but that suggests that they might be comparative inclusions, or perhaps simply stretching the definition for a specific illustration of trends, whereas normally they would not be included. If they are typos, so much the better, since then you truly have already covered everything that's been called a nonmetal. If they are not, then presumably you could say that some other elements are very occasionally included for comparative purposes. I seem to remember a source that admitted as much for polonium: let me see if I can find it. Double sharp (talk) 07:27, 3 September 2021 (UTC)


 * Found it: Sherwin, Weston, and Spice: Chemistry of the Non-Metallic Elements (Pergamon, 1966). Fig. 1.2 classifies as nonmetals the same elements that you consider, except that germanium is traded for astatine. (Hydrogen is put both above lithium and above fluorine; in the first capacity it stands on the metals' side of their line, in the second on the nonmetals'.) However, chapter V is titled "Group VIB", and includes polonium. It is there that the authors admit "The element [polonium] is best classified as a metal but its chemistry can only be conveniently studied in connection with Group VIB" (p. 69). For I suppose similar reasons antimony and bismuth are included in their chapter on Group VB (they call them both metals). Germanium, tin, and lead are only very briefly mentioned (pp. 154–6). Ge, As, Se, and Te are called metalloids. So, here's at least one of those cases where the authors admit that Po is quite metallic and therefore that they probably shouldn't be discussing it in a book about the nonmetals, but include it anyway to avoid splitting the story of a group. Double sharp (talk) 08:19, 3 September 2021 (UTC)


 * Sandbh comment: Remarkable! S&W set out further wisdom (as well as some mixed messages):
 * As you noted, they say Ge is a metalloid (p. 6) but show it as metal on the next page; also shown as nonmetals are B, Si, As, Se, Sb. Later they say Sb is a metal and that As is best called a metalloid (p. 115).
 * "We shall discuss the chemistry of the non-metals in relation to their positions in the periodic groups and where the groups contain metals, as in Group…[14], we shall, as necessary, discuss briefly their chemistry also to show the properties which occur." (p. 6)
 * "Whilst these heavier elements [Se and Te] look metallic they show the chemical properties of non-metals and therefore come into the category of "metalloids"." (p. 64)
 * "Po…resembles Te in many respects except that it shows no acidic properties and is more strongly basic. Po forms a normal sulphate, Po(So4)2, from the chloride and sulphuric acid, whereas Te forms a product, 2TeO2.SO3, usually described as a basic sulphate." (p. 69)
 * They mention a search for silicone type inorganic polymers, motivated by the lack of high thermal stability in organic polymers, is being conducted among -B-N-, -Si-N-, -P-O-, and -S-N- systems (p. 153) That's an example of a cross-group selection from the CHONPS that hadn't occurred to me.
 * "Tin and lead would figure high in the layman's selection of typical metals…Sn and Pb are typically not metallic in the truly chemical sense, but the weakly basic properties are responsible for their being so familiar since it is for that reason that they are so easily isolated from their ores and have been known for centuries…Its [Ge] chemical properties provide a link between the nonmetals and metals and it is now becoming better known…in view of the development of semiconductors, for which both Si and Ge have been found useful." (pp. 154–156)
 * "The binary compounds of many transition elements with certain non-metals form a particularly interesting group." (p. 164)
 * They mention the life-supporting roles of C, N, O, and P but say nothing about H, S, and Se in this regard (not saying anything about Se is no surprise given the role of selenocysteine was not then appreciated).
 * So they confirm that metalloids behave chemically like nonmetals; and that Po is best regarded as a metal but they got wrong the bit about it shows no acidic properties, since PoO2 is amphoteric.
 * What they say about tin is pertinent to our discussion about chemistry on Pluto.
 * Given what they said about inorganic polymers, it's notable they further hone in on a "particularly interesting group" of cross-cutting nonmetals or a sub-class i.e. H, C, N, which they say form interstitial compounds with TM. In fact, this ability extends to B, O, Si, P, S, (Se).
 * More generally they divided their book using the noble gases; hydrogen (a placement consistent with where the nonmetal article shows H); the halogens; and then the rest of the nonmetals in groups 16 to 13. Curiously, whereas they also provide an overview of groups 16, 15 and 14, they have nothing to say about the rest of the elements in group 13, which are all metals.
 * It's reassuring that they:
 * include the "metalloids" (Ge), As, Se, (Sb) and Te in a book on the chemistry of the non-metallic elements (B and Si are regarded by then as nonmetals); and
 * mention shared properties among the nonmetals that cut across groups i.e. interstitials; "biogens"; and inorganic polymers.
 * Sandbh (talk) 04:54, 5 September 2021 (UTC)

Unclassified nonmetals
The article also says, "In 2021 it was reported that the unclassified nonmetals could be collectively distinguished..." -- I am left thinking that if despite the fact that nonmetals have been known for centuries, it was only in 2021 (this year!) that there somebody reported some merit in justifying a common label for one category in this grouping, then maybe this is not really a common category and thus it shouldn't be given that much limelight. Also, I can spot a weasel phrasing here, which makes me even more suspicious (even if you change your wording, however, the original concern about whether this grouping is that important at all remains).


 * Sandbh comment (a): A basic taxonomy of the nonmetals was set out by Dupasquier, a French doctor, pharmacist and chemist, some one and three-quarter centuries ago. To facilitate the study of metalloids (i.e. nonmetals), he wrote that, “they will be divided into four groups or sections, as in the following table:”
 * {| class="wikitable"


 * Section || Name || Constituents
 * 1st || Organogens || O, N, H, C
 * 2ns || Sulphuroids || S, Se, P
 * 3rd || Chloroides || F, Cl, Br, I
 * 4th || Boroids || B, Si
 * }
 * 3rd || Chloroides || F, Cl, Br, I
 * 4th || Boroids || B, Si
 * }
 * 4th || Boroids || B, Si
 * }


 * Sandbh comment (b): The unclassified nonmetals thus encompass the organogens and the sulphuroids. See: Dupasquier A 1844, Traité élémentaire de chimie industrielle, Charles Savy Juene, Lyon, pp. 66–67.


 * Sandbh comment (c): After that:
 * the chlorides later became referred to as the halogens;
 * the boroids came to expand into the metalloids, starting from as early as 1864 (to my knowledge); and
 * varying combined configurations of the orgaongens and the sulphuroids came to be haphazardly referred to as e.g. basic nonmetals; bioelements; biogens; central nonmetals; CHNOPS; essential elements; "nonmetals"; orphan nonmetals; other nonmetals; primordial nonmetals; or redox nonmetals;
 * the noble gases, as a discrete grouping, joined the nonmetal club from ca. 1904.


 * Sandbh comment (d): The key takeaway is the recognition of three to four kinds of nonmetal i.e. metalloids, halogens, and noble gases more or less firmly carving out their periodic table patches, to either side of the leftover nonmetals. That is to say, in an article about nonmetals, one is obliged to say something about the unclassified or leftover nonmetals, simply because they are what it is left after the metalloids, halogens, and noble gases.
 * Fixed. As per preceding "Done". Sandbh (talk) 07:41, 25 August 2021 (UTC)
 * Thanks for some context.
 * I note that none of what you just said is in the article, where it would matter more. If it were there, however, I'd immediately point that the "after that" part is the most important one in this story, and it's not described in detail here. Perhaps that could be elaborated on, but the suggestion I maintain is that you're better off scrapping this categorization altogether in favor of some loosely defined groupings that are not necessarily constrained by the nonmetals class, such as "halogens" (instead of "halogen nonmetals"), "metalloids" (they're also here now, but they don't have to be a subclass of the nonmetals), "chalcogens" (for reasons similar to "halogens"), etc.--213.24.133.229 (talk) 16:11, 28 August 2021 (UTC)
 * Comment Sandbh (talk) 07:35, 30 August 2021 (UTC)


 * Sandbh comment: I didn't include the history of the classes as I'd originally intended for the article to be boutique style rather than another relatively massive doorstop such as metalloid. And the classes had been around for 150 years without change. The only excitement was the varying ways of referring to the other nonmetals. The history has now been incorporated into one of the footnotes, including several examples of collective names for the orphaned other nonmetals.


 * Last year I looked up the taxonomical structure of lede periodic tables found in 62 more recent chemistry textbooks. 10% showed groups such as Chalcogens (~1.5%); Halogens (11%); Noble gases (~19%). The other 90% instead showed different selections from the following range:


 * {|class="wikitable"

! Metals !! More metals !! Nonmetals !! Sundries
 * - valign=top
 * Active metals
 * Reactive metals
 * Light metals
 * Rare earths
 * Actinides
 * Lanthanides
 * Inner transition elements/metals
 * Metals (inner transition)
 * Transition metals
 * Metals (transition)
 * Post-transition metals
 * Poor metals
 * Hydrogen
 * Metalloids aka semi-conductors/semimetals
 * Other nonmetals
 * Life elements
 * s, f, d, and p blocks
 * Gas-liquid-solid
 * Main group elements
 * Main group metals
 * Metals (main group)
 * Representative elements
 * }
 * Main group metals
 * Metals (main group)
 * Representative elements
 * }


 * In the Subclasses section of the article, the subsection heading for metalloids now reads as "Metalloids(?)". Under that heading I've added an opening 1-sentence explanatory paragraph saying, "The question mark denotes that metalloids may or may not be regarded as a nonmetals or as a subclass of nonmetals, as discussed in the Subclasses section." I feel this is appropriate as 1-sentence paragraph. Sandbh (talk) 00:04, 31 August 2021 (UTC)

Alternative nonmetal subclasses
The article even says, "This section describes one approach to subclasses of nonmetallic elements; for other perspectives, see List of alternative nonmetal classes." So other kinds can be discerned, too. It is even less clear then why this particular approach was chosen above all else.

It is important to remember one very important distinction between Wikipedia and journal articles from the reader's perspective: journal articles have explicit authors, and whatever an article says can be attributed to a person, a group of people, or an institution. Whether they are right or wrong (and it's not unheard of that science can be wrong), there's somebody to attribute that to. There is nothing like that in Wikipedia, however, and people are less likely to question it, there is little incentive to do so, even despite Wikimedia's constant pleas to not treat Wikipedia as an authoritative source. This is because Wikipedia commonly takes (or at least tries to take) an unpersonalized position on most issues, so its contents are often seen as "common wisdom." This is, in fact, something the original concept of Wikipedia was about and something that is deeply reflected in Wikipedia's core policies.

With this in mind, it is rather strange and even somewhat unsettling to see that a very particular position is assumed here. Some smaller Wikipedias have this problem, but the English Wikipedia is generally known to be above that. I want to stress I wouldn't say a word about this if we were discussing a journal article, with the name of its author in the heading, but we're not discussing one.


 * Sandbh comment: To some extent, one can attribute a wp article to its lead editor, but that has its limitations given the relative anonymity of our wp names. I do like your notion of common wisdom, since I feel this easily applies to metalloids, halogens, and noble gases. By default, there is a remaining set of nonmetals. I don't see anything being very positioned here. It is instead the situation found in the literature.
 * Fixed. I've copyedited the article to make it clearer that the subclasses involved are the more common ones, and that (less common) broader or more specialized subclasses can also be found. The changes involved can be found in the lede and in Subclasses. Sandbh (talk) 03:24, 25 August 2021 (UTC)

Taking a position

 * It's not the same really. When this article gets a bronze star, it won't be seen as an article written by Wikipedia user Sandbh, it will merely be a Wikipedia article. In fact, you have to look for article stats to see who contributed to it (most readers probably don't even know Wikipedia has article stats). This is very different from journal article, which do have authors and are attributed to either them or their institutions ("a University of Oxford study showed that..."). It is fine to take any position provided you dress it like a position that can be explicitly attributed to someone. However, the existence of the "nonmetal halogens" category is not common wisdom by any means.--213.24.133.229 (talk)
 * Sandbh comment: Elsewhere I've explained that "nonmetal halogens" is an expression of convenience, similar to e.g "liquid bromine", is this passage: "Antimony ignites in bromine vapor and reacts explosively with the liquid halogen." Or this passage: "Light halogens, fluorine (F) and chlorine (Cl), at normal conditions are highly reactive and toxic gases." And I've given multiple examples of the use of "nonmetal halogens" in the literature, including in mundane chemistry textbooks. Essentially, the chemistry of the halogens F, Cl, Br, I is comprehensively set out in the literature, and this is the common wisdom encapsulated in the descriptive phrase "nonmetal halogens". While the term "halogens" is widespread, it transpires that when authors and scholars feel a need to be more specific, the expression "halogen nonmetals" evidently appears. Here there is a purposeful distinction between "halogens" as a collective name for the group 17 elements from F to At, and the nonmetals F to I. I see no value in compounding the situation unnecessarily by referring to e.g. nonmetal group 14 elements; nonmetal pnictogens; or nonmetal chalcogens. Sandbh (talk) 00:57, 31 August 2021 (UTC)

An expression of convenience

 * If it is true that "nonmetal halogens" is merely an expression of convenience, as you say, then you should not treat it as an actual category name. This is clearly what the article is doing presently, however. The claim that "nonmetal halogens" is an expression of convenience does not sit well with the idea that you have a table in the article titled "Some cross-subclass physical properties," in which "Nonmetal halogens" is one identified subclass. This is not an expression of convenience, this is a category name, one that is not common in the literature at all. You have a section titled "Subclasses," where "Nonmetal halogens" is one subsection, and after that I can't find that "nonmetal halogens" is merely an expression of convenience. You could remove that category name for the table and that subheader to make it look like we're not talking about a category name (subclass, as the article says).
 * In fact, out of examples of the "nonmetal halogen" name you provided, it is evident that some of those quotes are indeed expressions of convenience, unlike in the article. Even at that, those name occurrences are vastly outnumbered: as I mentioned above, Google Ngram shows that the phrase "halogen nonmetal" is four orders of magnitude (i.e., 10,000 times) less common than "halogen."
 * In fact, the metal article, as I discovered today, does a good job at not overstating the importance of common names (even actually common names, like "alkali metal"), and the example of the article is something I've been suggesting all along, but it's formulated much better than in my review here.--213.24.134.134 (talk) 14:09, 11 September 2021 (UTC)


 * Sandbh reply: The non-issue as I see it is that effectively the entire chemistry community treats the halogens as effectively being F, Cl, Br, and I, given the minuscule number of them that work with At. While the expression "nonmetal halogen" is not so common, that is because when the term "halogen" is employed it is automatically assumed that halogens are nonmetals. Hence, there is ordinarily no need to say, "nonmetal halogen" because to do so would be redundant.


 * Reinforcing my point, it's common to see tables in chemistry books that compare the properties of the halogens being limited to F-Cl-Br-I. G&E for example do this for physical properties of the halogens; stereochemistry of the halogens; physical properties of the hydrogen halides; comparison of diatomic halogens and their cations; and oxoacids of the halogens. That is to say, these tables all refer to "the halogens" as F-Cl-Br-I. Since everybody knows they are nonmetals there is no need to say "nonmetal halogens".


 * Yet the expression "nonmetal halogens" is occasionally found in the literature, including in introductory chemistry textbooks, and Hawley's Condensed Chemical Dictionary.


 * I agree with you that some of the literature extracts I provided you with use "halogen nonmetal" as an expression of convenience. It's used the same way in the article. When it comes down to it, all such terms such as alkali metals, transition metals, metalloids and "other nonmetals" are expressions of convenience.


 * Currently, I feel this is a non-issue that could be best addressed by way of a carefully worded footnote. Sandbh (talk) 05:54, 12 September 2021 (UTC)

At, "metal" & stable halogens
Regarding G&E, they do title their chapter "The Halogens: Fluorine, Chlorine, Bromine, Iodine and Astatine". However, only for the first overview sections (history, abundance/distribution) is At actually covered at length with the others. Most information about astatine was quarantined to the very last section ("The chemistry of astatine"). My impression is that this is not at all unusual. I guess a chemist directly questioned about whether At is a halogen would probably say yes, but I find it likely that the same chemist writing loosely about halogens is not really thinking about At. You know, I asked about this last year at Wikipedia talk:WikiProject Elements/Archive 56, and he said: I wasn't particularly aware that astatine was coming to be seen more as a metal than a metalloid. I've never worked with it and don't know anyone who has. My guess is that most would view At as a halogen just from being in group 17, but that more as a default that a considered analysis of the term "halogen"... though organic chemists do often limit the term halogen to those typically used. (His ellipsis.)

I think metal is not a good comparison, because alloys like steel are often also called metals, so it is not just about elements. Nonmetal does usually seem to be about elements, I think.

In any case, why all the fuss? Predictions say astatine is a metal, but we don't have experimental proof of it, just somewhat suggestive data. And it seems to be a non-issue owing to its scarcity, except for the few who actually work on it. I mean, you're not discussing it much here, but would you be discussing it much either if it had turned out to be a predicted iodine-like semiconductor? I suspect not, since you don't discuss Og much either. So I'd say it's a non-issue. Though, how about "stable halogens" instead as the name, to make it look even less like a category name? Double sharp (talk) 07:16, 12 September 2021 (UTC)
 * Sanbdh reply: Stable halogen looks like a very strong possibility! Let me see how that reads in the article. About 3.5 times as popular as nonmetal halogen according to Ngram. Sandbh (talk) 08:28, 12 September 2021 (UTC)
 * Sanbdh reply 2: It turns out that F, Cl, Br, and I are also referred to as “common halogens”. In the end I stayed with nonmetal halogens and added three cites apiece for each of the three terms, in the lede of the Subclasses section. I feel it now hangs together quite well. Sandbh (talk) 13:16, 13 September 2021 (UTC)

The tetrachotomy
IP editor post: Personally, I think the bigger issue at hand is, there is little reason for the tetrachotomy to be in the article. While halogens, noble gases, and metalloids are indeed well-established sets of elements, there is no reason they must be differentiated at the same time in this article to form a comprehensive categorization other than an editorial choice, one which I believe to be inconsistent with Wikipedia's house rules or at least my understanding thereof. I'm suggesting a remedy to that, but I believe the best thing to do would be to abolish the tetrachotomy altogether, in the same manner as the metal article does not seek to divide the elements into the sets of alkali metals, alkaline rare earth metals, lanthanides, actinides, transition metals, and post-transition metals (which it could, but wisely does not). That being said, my opinion is only an opinion, and I'm glad this is a peer review, meaning that my opinion is of no immediate consequence. I'm not holding you from anything by merely disagreeing with you, and if others don't share my opinion, so be it. There's often a chance I'm wrong without realizing it, or at least that others' understanding is different than mine, in which case the failure to realize it is on me. That's exactly why I'm not coming to the upcoming FAC.--213.24.126.91 (talk) 18:46, 12 September 2021 (UTC)


 * Sandbh reply: The metal article is not so comparable in the way you attempt. First, it is not as advanced as the nonmetal article. Second, it has a table that categorises the elemental metals into a hexachotomy, on the basis of their chemical properties, i.e. alkali and alkaline earth metals; transition and post-transition metals; and lanthanides and actinides.


 * Further considerations are that the wp colour coded PT, which is a good one, half way down the article, features a nonmetal tetrachotomy. The caption to that table has a link to the ACS PT, also nicely done, and it too has a nonmetal tetrachotomy.


 * For the nonmetal article, some editorial choice needed to be exercised in assessing the literature and how to convey the knowledge set out therein into the article. The founders of the wp table did this about 20 years ago. The result was that in right half of the table they had semimetals/metalloids; nonmetals/other nonmetals; halogens; and noble gases, i.e. a tetrachotomy. Not much has changed in the literature in meantime. The recent Nature article that surveyed > 3,000,000+ abstracts confirmed the wisdom of the founders. Sandbh (talk) 13:04, 13 September 2021 (UTC)


 * IP editor reply (1): It appears to me you're reading into my words too much, and that's why the comparison does not work. The metal article may not be as advanced as the nonmetal article, but I never claimed otherwise or relied on that. My point was that the categorization in the metal article was desirable and worth reproducing. That's it. I also can't find the table in that article that features the said hexachotomy; would you point me to it?
 * The table in the middle of the periodic table is not the wp table; this one is. There is a reason why the old table is no longer used, namely that divisions like we had are still rather arbitrary (if I recall correctly, that was the reason why suggested getting rid of the old classification in the first place, though I stand open to corrections). It is far from obvious that the lanthanides should take precedence over rare-earth metals (something I was in favor of) or that the platinum group metals should not be displayed. At the same time, it had two categories that were not legitimate on their own but only in a bigger classification, "post-transition metals" (as much as I wanted that to be a thing) and "other nonmetals." And even at that, the way that classification was used back in the day was less categorical than the current suggestion: the elements were divided into groups much for the sake of being divided into groups because that was useful in an infobox where room is limited. This is not required in an article, which can provide a fuller picture.
 * Again, WP:ELEM founders had a different goal in mind than the one you have now, so the comparison does not really hold water. They never (AFAIK) sought to use that to categorize all elements in an article, rather than in a secondary graphic; if they did, I would be opposed to that (maybe not at the time, but certainly today).--213.24.126.91 (talk)

General nonmetal behaviour
Double sharp post: Well, IIRC my reason was simply that there wasn't really a consensus among chemists where the category boundaries were to be drawn (e.g. are germanium, antimony, and polonium metals or metalloids?), and that the different options were all common enough that drawing the line in any place took a side against too significant a minority.

But, noble gases are pretty different from the others chemically, and it seems natural to discuss them separately. The fact that the metalloids are sometimes included and sometimes not also suggests to discuss them separately.

So that leaves halogens vs the other ones. Here I somewhat agree that we did not have to divide it this way, because indeed oxygen is on a par with chlorine in strength. (So yeah, when the article says the other ones form interstitial compounds with metals, I am not so sure regarding oxygen.) And nitrogen and sulfur, with iodine. And small size of 2p favours multiple bonding, so I definitely think that nitrogen and oxygen do not really have the ability to catenate, contrary to what the article currently says. (Not to mention hydrogen. Actually, I think exceptional status of quasi-metal hydrogen should really be mentioned, shouldn't it?) That said – I am pretty sure that halogens are put together by almost everybody. At least the stable ones.

So, an idea: why not try talking about general nonmetal behaviour instead (so they become stronger as you go to the top and the right side, to cover the nitrogen and oxygen issue)? There are not that many of the normal ones. I have some ideas about how to write it, if doesn't mind me sandboxing a proposed version. Double sharp (talk) 04:53, 14 September 2021 (UTC)
 * IP editor reply: I also like the idea, it seems just right to me. If my assistance is of any use, just let me know.--213.87.163.199 (talk) 06:47, 14 September 2021 (UTC)
 * Sandbh comment: Please see my note about this towards the end of the Untowards subsection Sandbh (talk) 07:27, 18 September 2021 (UTC)

Tetrachotomy cont.(A)
Sandbh reply to IP editor(1): The metal hexachotomy in the metal article is to the left of the category section. I've reproduced it here (i.e. "Metallic elements") next to one of my earlier posts.
 * The table you refer to as "the wp table" is not the wp table. Rather, the table that appears in the lede of the periodic table article is the 32-column black and white one, as I've posted here.
 * My reference was to the wp colour-coded table which appears in the periodic table article, and not, as you put it, to the wp periodic table.
 * I don't understand the philosophy behind not discussing sub-classes in an article on either metals or nonmetals. For example, the metal article currently describes the subclasses of ferrous and non-ferrous metals; brittle metals and refractory metals; white metals; heavy and light metals; and base, noble, and precious metals. The nonmetal article has discussed subclasses since 2013.
 * Powell & Timms (1974) in their book The Chemistry of the Non-metals, at one point divide the nonmetals into three groups according to their volatility:
 * gases at room temperature (H, N, O, F, Cl, and the NG);
 * condensed phases of intermediate bp (P, S, As, Se, Br, I); and
 * condensed phases of high bp (C, Si, Ge, Sb, Te).
 * They say this is a "useful sub-division" because of the simple relationship between volatility and the structures of the elements.
 * Elsewhere they distinguish oxides of the nonmetals as being either:
 * monomeric (e.g. F2O);
 * partly of weakly polymerized (e.g. P4O6); or
 * polymerized/giant lattices (e.g. GeO2).
 * They further distinguish between:
 * the 'ideal' behaviour of the noble gas atoms; and
 * the uncomplicated forms of the halogens (F, Cl, Br, I only; At is counted by them as a metal); compared with…
 * the nonmetals of the previous groups.
 * P&T take up about 81,300 words (exc. index). The nonmetal article, inc. footnotes, runs to roughly 10,000 words. My point is that while the wp article cannot go into the same kind of depth it can at least cover the highest level of similarities in order to bring some further structure to its coverage.
 * The popular LANL periodic table, as mentioned from time to time at WP:ELEM, divides the right half of the periodic table into metalloids; nonmetals; halogens; and noble gases.
 * On the metal side of the house, for example, Parish (1977) in The Metallic Elements, divides them into the s-block metals; the 3d metals; the 4 and 5 d metals; the Ln and An; and the p-block metals. He notes the Group VIII metals are "often grouped together" as the platinum metals, and that they together with and Ag and Au "are often known" as the noble metals.
 * Pattern recognition of the properties of the elements, as opposed to a huge collection of facts, is a fundamental concept dating back to the days of Dupasquier (1844), and his subdivision of the nonmetals into five kinds, and later to Mendeleev and Meyer.
 * Or consider this quote:
 * "Describe how groups of elements can be classified…including…highly reactive [halogen] nonmetals, less reactive [unclassified] nonmetals, and some almost completely nonreactive [noble] gases."
 * --- Padilla MJ, Cyr M & Miaoulis I 2005 Science explorer (Indiana Grade 6), Teachers's edition, Prentice Hall, Upper Saddle River, New Jersey, p. 27.
 * In the above context,I feel the inclusion of subclasses in the nonmetal article provides a fuller picture, as you say. Sandbh (talk) 06:58, 14 September 2021 (UTC)
 * DS on a fuller picture: What you say is true, but in my opinion, we would get an even fuller picture if we included more possible subclasses. Well, you talk about the metal side of the house: it's common to give alkali, alkaline earth, Ln, An, transition, and the other ones. That's what LANL does. As you note, however, Parish gives different categories! He combines alkali and alkaline earth metals into s-block metals, whereas he splits the transition metals into the 3d metals and the 4d/5d metals. As well, he mentions platinum (group) metals and noble metals. These categories overlap. And of course, for other purposes there may be other categories worth noting, e.g. lithophile vs chalcophile vs siderophile metals. I think it would serve the metal article better if all those possibilities were mentioned.
 * In other words, while I accept and agree that we get a full picture by noting commonalities among the stable halogens: I see no reason why that should not also be true of the pretty homogeneous stable chalcogens too, for example. Or similarly Wulfsberg's distinction into very electronegative vs (just) electronegative nonmetals. The category scheme we currently provide is a good one, but it isn't the only one around, and for many purposes other categories are more natural. I do feel that we should acknowledge that. Double sharp (talk) 13:12, 14 September 2021 (UTC)
 * Sandbh reply: Quite so, and agreed! The nonmetal article used to have a section listing the different ways of parsing the nonmetals, including that of Wulfsberg, and the group-by-group approach. My impression is that the tetrachotomy is the most common approach, given (i) At is often ignored, and (ii) the strong identities of (a) the four halogens as a set, and (b) the noble gases group. To sharpen the focus of the article, and to contain its length, I hived the other taxonomy content off into its own child article. So the start of the subclasses section now reads:
 * "Approaches to classifying nonmetals may involve from as few as two subclasses to up to six or seven. For example, the Encyclopedia Britannica periodic table has noble gases, halogens, and other nonmetals, and splits the elements commonly recognised as metalloids between the "other metals" and the "other nonmetals"; the Royal Society of Chemistry periodic table shows the nonmetallic elements as occupying seven groups.
 * This paragraph was originally the last in the subclasses section. I moved it the front, in light of feedback here, and as I thought it gives a good introduction to the topic.
 * I felt this was a reasonable solution. Sandbh (talk) 00:15, 15 September 2021 (UTC)

Tetrachotomy cont. (B)

 * I think Double sharp is on the spot here.
 * My impression is different from yours, and that is, presumably, where our difference comes from.
 * My impression is that metalloids are not treated as a subset of nonmetals. While that could be said, in principle, about halogens and noble gases, I am far from certain the same necessarily holds for the metalloids. Our dividing line between metals and nonmetals article shows a line which bisects the metalloid class into a metallic and a nonmetallic part rather than count them all as nonmetals. I have seen the line drawn this way on a few other occasions, and I am certain this is the most common way to distinguish nonmetals from metals. However, our article does not make a serious attempt to differentiate between the nonmetallicity of germanium and antimony on one hand and arsenic and tellurium on the other. The attempts to differentiate carbon from boron seems to be less important (both elements are commonly counted as nonmetals), and yet that differentiation is there while Ge-As is not. Words like "each categorization is vague and exact composition of each group can differ by source" wouldn't cut it for me. If anything, I could suggest using the same left border of the nonmetal set as in dividing line between metals and nonmetals and then say that categorization may vary by source. In that regard, I believe the article does not portray the consensus in the literature very precisely, although I do note that there are occurrences when even germanium is counted as a metal.
 * It is also my impression that there are few, if any, paperback periodic tables that feature halogens, noble gases, and metalloids in their primary classification at the same time. I do acknowledge the online periodic tables you mentioned, but this is not a killer argument as I see it. More books like G&E would impress me more.
 * Finally, even if it were the case that there were sources, I would still not think it is right to focus on these subdivisions as much as the nonmetal article does. Saying that, I want to note I am more or less fine with the hexachotomy in the metal article. I see it as merely a way of elements that needs to be divided somehow in order to be parsed by a reader more easily. There are no subsections for these categories in the article and there are no pictures that divide the metals into six categories. If you imitate the metal approach on this, I'll think it is fine and I'll be ready to withdraw my concerns.
 * I realize the best way to overcome this difference in perceptions is best overcome by trying to understand the other side. Having read this page, I still don't understand where exactly your impression on this comes from; I do think that it is a) not common to focus on halogens, noble gases, and metalloids at the same time, and b) there is no reason to distinguish these groups as much as you do. However, me not understanding something does not necessarily mean there is nothing to be understood, and perhaps by trying to combat this message you can help me see something I'm missing.
 * I do think, however, that DS's proposal to say "these nonmetals" rather than "unclassified nonmetals" is a right one, so that people don't think there is a category where there is none. It's a step in the direction I'm trying to outline.--213.24.126.91 (talk) 13:48, 20 September 2021 (UTC)

Sandbh reply to IP editor: I've added hash marks to your comments so that they are numbered; my reply addresses these.


 * Your post is 600 words, mine is 4½ times that. It's easy for an editor to raise concerns. It's harder to set out how much research and how many considerations went into the areas of concern before the original editor uploaded the associated content.

At the outset I feel it's important to bear in mind that the focus of the article is "nonmetals in chemistry" rather than "nonmetals in Groups", as such. In taxonomical terms the low hanging fruits are the noble gases; and the halogens (often ignoring At, as DS noted, and as cited). Metalloids are lower hanging too, although how they are treated with respect to nonmetals varies by author, as discussed in the nonmetal article. What happens to the rest of the nonmetals likewise varies by author, depending on their perspective of interest. I've chosen to not drill down below this level, in the main body of the article, since we already have articles covering
 * (i) each p-block Group;
 * (ii) the CHON nonmetals;
 * (iii) the nonmetals on a group-by-group basis;
 * (iv) alternative nonmetals classes; and
 * (v) each nonmetal element.

1. Yes, I agreed with Double sharp. Did you read my reply to him?

2. I've never said "metalloids are treated as a subset of nonmetals" as you implied. Instead, as the article makes clear, this is but one option for dealing with metalloids:


 * "…the chemically weak nonmetallic metalloids,[94] sometimes considered to be nonmetals and sometimes not.[n 17]


 * "Since the metalloids occupy frontier territory, where metals meet nonmetals, their treatment varies from author to author. Some consider them separate from both metals and the nonmetals; some regard them as nonmetals[96] or as a sub-class of nonmetals;[97] others count some of them as metals, for example, arsenic and antimony due to their similarities with heavy metals.[98][n 18] Metalloids are here treated as nonmetals in light of their chemical behavior, and for comparative purposes."

The lede text before the comparative tables adds:
 * "The dashed line around the metalloids denotes that, depending on the author, the elements involved may or may not be recognized as a distinct class or subclass of elements."

3. Our article on dividing line between metals and nonmetals is not up to FAC standard. That needs to be borne in mind when seeking to rely on it. The dividing line article does not actually…


 * "show a line which bisects the metalloid class into a metallic and a nonmetallic part"

…as you put it. Although I can see how the title of the article could give that impression.

The article instead says:


 * "Elements to the lower left of the line generally display increasing metallic behaviour; elements to the upper right display increasing nonmetallic behaviour."

The History section of the article is misleading since it only gives examples that supposedly do divide the metals from the nonmetals.

That said, the Concerns section makes it clear that many objections have been raised about the idea of a sharp distinction between metals and nonmetals.

Anyway, instances in the literature of a so-called dividing line between metals and nonmetals need to be scrutinised to see what the author actually says in the accompanying text. For example, an author may say that the line is only indicative or that metalloids or semimetals are found to either side of the line. And one then has to check how the author actually treats the metalloids or semimetals in the rest of the text.


 * Jones & Atkins (1999), for example, in Chemistry—Molecules, Matter and Change, 4th ed., say a metalloid is:


 * "An element that has the appearance and some physical properties of a metal but behaves chemically like a nonmetal."


 * Their feature PT shows the metalloid cells with a heavier border, rather than showing a single dividing line.


 * For another example, Jardins (1957, Vitalized Chemistry, 4th ed.) shows a traditional dividing line. This author treats O, S, F, Cl, Br and I as "leading" or "typical" non metals" leaving H, C, N, P, and Se as nonmetals; and the inert gases. Jardins also regards F, Cl, Br and I as halogens. Boron is regarded by him as a borderline element; Si is shown as a nonmetal in his periodic chart, while elsewhere he refers to Si as a metal; Ge is shown as a metal, As as a nonmetal, and Sb as a metal. Later he writes that As and Sb have some of the physical properties of metals but, "since their oxides form acids, they are usually considered as non-metals." Te is shown on his chart as a nonmetal. Jardins does not refer to metalloids or semimetals. The 1st edition appeared in 1942, and a 6th edition appeared in 1964 or 1965, so it must have had some credibility. I have a hard copy of the 1946 edition purchased by the original owner in 1948.


 * You may be familiar with Atkins' (1995) book, Periodic Kingdom, in which he treats the PT as a country, and provides a travel guide. He too refers to metalloids, halogens and noble gases. No mention of pnictogen nonmetals or chalcogen nonmetals, let alone "pnictogens" or "chalcogens". For the rest of the nonmetals he refers to a small area of the kingdom in which there are the building blocks of life: C, N, O, and P. For Se, As, Te and Sb he says they lie in regions that nature has hardly sought to exploit. Boron he refers to as a typically nonmetallic element along with N.


 * Olmsted and Williams (1997, 2nd ed.) in Chemistry: The Molecular Science divided the right half of their feature table into main group elements (i.e. the metals between the TM and the metalloids, and the nonmetals between the metalloids and the halogens); metalloids; halogens and noble gases. I mention them since their work was unique among general chemistry texts for the extent that it emphasised an atomic and molecular point of view, and for its more conceptual focus. The 1st ed. appeared in 1994; the 5th in 2014.


 * Taylor et al. (2007) in Study on Chemistry 1, is an Australian textbook for year 11 students. The first periodic table in its chapter on "The development of the periodic table" includes the date of discovery of each element, and is colour coded to show metalloids; non-metals; halogens; and noble gases.


 * Please don't forget the 2020 article by Kaiser and four colleagues (now with 87 citations), which parses the right side of the PT into metalloids; nonmetals (H, C, N, O, P, S, Se); halogens; and noble gases.

4. Contrary to your assertion that the nonmetal article does not attempt to differentiate Ge and Sb from the rest of the metalloids, the article includes this note:


 * The elements involved may instead be classified on a case-by-case basis.[97] For example, germanium[98] and antimony[99] may be counted as metals or selenium may be admitted to the metalloid club.[100]


 * The considerations of authors in making these decisions may or not be made explicit and may, at times, seem arbitrary.[101] A binary classification can facilitate the establishment of rules for determining bond types between metals and nonmetals.[102] Alternatively, classifying some elements as metalloids "emphasizes that properties change gradually rather than abruptly as one moves across or down the periodic table".[103] Oderberg[104] argues on ontological grounds that anything not a metal is therefore a nonmetal, and that this includes semi-metals (i.e. metalloids).


 * Jones[105] takes a more philosophical or pragmatic view. He writes: "Though classification is an essential feature of all branches of science, there are always hard cases at the boundaries. The boundary of a class is rarely sharp…Scientists should not lose sleep over the hard cases. As long as a classification system is beneficial to economy of description, to structuring knowledge and to our understanding, and hard cases constitute a small minority, then keep it. If the system becomes less than useful, then scrap it and replace it with a system based on different shared characteristics."

5. You say:


 * "words like 'each categorization is vague and exact composition of each group can differ by source' won't cut it for me."

They don't for me. Neither nor does the article use such words. What the article instead says is:


 * "The distinction between different kinds of nonmetals is not absolute. Boundary overlaps, including with the metalloids, occur as outlying elements among each of the kinds of nonmetals show or begin to show less-distinct, hybrid-like, or atypical properties."

And later:


 * "Aside from the metalloids, some boundary fuzziness and overlapping (as occurs with classification schemes generally) can be discerned among the other nonmetal subclasses. Carbon, phosphorus, selenium, iodine border the metalloids and show some metallic character, as does hydrogen. Among the noble gases, radon is the most metallic and begins to show some cationic behavior, which is unusual for a nonmetal.[106]"

6. Adding a stair-step line is a good idea. I've added such a line to the subclasses table, together with explanatory text in the table caption.

7. For paper sources that feature halogens, noble gases, and metalloids in their primary classification at the same time, I mentioned two of these earlier, and Double sharp mentioned the ACS periodic table. This is available in wall poster form from the ACS shop.


 * G&E certainly discuss halogens, and noble gases. They explicitly refer to Ge, As and Sb as metalloids or semimetals. At another point they refer to B, C, Si, Ge; P, As, Sb; Se as nonmetals (p. 662). Te is referred to as a nonmetal (p. 168). Notably, they refer to P, H, C, N, O and S as being essential to life (p. 476) and that Se was found (in 1957) to play an essential dietary role in animals and also in humans (p. 759).


 * Even Scerri (2013) gets into the act, in 30-Second Elements: The 50 Most Significant Elements, Each Explained In Half a Minute. There is a stellar array of contributors to this tome: Hugh Aldersey-Williams; Philip Ball (ex-Nature editor); Brian Clegg; John Emsley; Mark Leach; Jeffrey Moran; Eric Scerri; Andrea Sella; Philip Stewart. The featured periodic table colour codes the p-block as: post-transition metals; metalloids; other nonmetals; halogens; noble gases. H is over Li and coloured as an "other nonmetal".

8. You go on to say:
 * "Finally, even if it were the case that there were sources, I would still not think it is right to focus on these subdivisions as much as the nonmetal article does."

What you think is one thing. What reliable sources say is another. I can cite the latter but not the former.

In any event, as you acknowledged earlier, the sets of metalloids, halogens and noble gases are more or less well established in the literature. By default that leaves H, C, N, O, P, S and Se. I have mentioned this phenomenon about ten times.

In response, on one occasion, you wrote:


 * "…there is absolutely no imperative that the article use a scheme in which any element must belong to a category, the set of which must also be mutually exclusive, hence there is no need for a leftover category. This will rather mark that the article does a fair job at describing the existing categories, thus presenting richer encyclopedical knowledge rather than creating new basically unheard of categories: that is the job for primary sources, not an encyclopedia."

The article acknowledges that categories can overlap, and gives examples of these. It discusses the well established (as you have acknowledged) classes of noble gases, halogens, and metalloids. Since At is often ignored, the article refers to F-Cl-Br-I as "halogen nonmetals", together with three cites. I previously posted further examples from the literature showing the use of this expression or derivatives thereof. The article further provides six cites referring to F-Cl-Br-I as either “common halogens” or “stable halogens”.

The article notes that some or all of the remaining nonmetals are encompassed by various class names, none of which are widely recognised. It has a link to the alternate nonmetal classes article which shows how the remaining nonmetals are sometimes instead treated.

For the default nonmetals the article lede says…
 * "The latter have no widely recognised collective name and are hereafter informally referred to as "unclassified nonmetals"."

…and in the main body:
 * "They are generally regarded as being too diverse to merit a collective examination,[141][52] and have been referred to as other nonmetals,[142] or more plainly as nonmetals, alongside metalloids and halogens.[143]

9. You go on to say:
 * "I am more or less fine with the hexachotomy in the metal article. I see it as merely a way of elements that needs to be divided somehow in order to be parsed by a reader more easily. There are no subsections for these categories in the article and there are no pictures that divide the metals into six categories."

As noted, the metal article is not up to FAC standard. The comparison is not valid.

In any case, there is a table in the metal article giving the hexachotomy. A table is simply another written communication mode, in the same way that a picture is worth 1,000 words.

10.

(i) My impression comes from the literature, which more or less routinely refers to metalloids; halogens (commonly ignoring At); and noble gases, noting it has been known for over 120 years that metalloids predominately behave chemically like nonmetals. Or, for example, there is this quote:
 * "Metalloids are much more like nonmetals than metals."
 * — Brady JE, Peck L & Humiston GE 1986, Solutions Manual for General Chemistry: Principles and Structure, 4th ed., John Wiley & Sons, New York, p. 46

(ii) My impression is also informed by the founders (in 2002–2003) of the wp colour category periodic table, who consulted the literature and came up with the same nonmetal classes.

(iii) My impression was confirmed by the 2019 article in no less than Nature, which surveyed three &#8251; &thinsp;million&thinsp; &#8251; abstracts and confirmed the presence of the four clusters of metalloids, halogen nonmetals, and noble gases, with a leftover cluster between the metalloids and the halogen nonmetals. As the authors themselves noted:
 * "Chemically similar elements are seen to cluster together and the overall distribution exhibits a topology reminiscent of the periodic table itself."

(iv) In the nonmetal article I took the approach seen in the metal article as mentioned by you i.e. as a way of dividing the elements somehow in order to be parsed (or chunked) by a reader more easily. Indeed, using “natural” classes or clusters to organise information is consistent with the cognitive-load theory of breaking up information into discrete or more easily memorisable factors i.e., chunking of information, and helps with content processing.

(v) Moreover, this approach is consistent with Ashford (1967):
 * "The failure to classify unambiguously all the elements into metals and nonmetals may appear, at first sight, as a weakness in the distinction. However, the difficulty is inherent in any scheme of classification of natural objects. In any attempt to classify a large number of natural objects into two classes, we almost invariably find all four logical possibilities. Some objects fall distinctly into one class, some fall into the other class, some belong to both classes and some belong to neither. Recognizing this fact, we continue the classification by making use of the degree to which they show these properties." (p. 329).
 * — From Atoms to Stars: An Introduction to the Physical Sciences, 2nd ed., Holt, Rinehart and Winston, New York

(vi) Consistent with Ashford, the clusters of metalloids, leftover nonmetals, and halogen nonmetals show increasing degrees of nonmetallic character i.e. from weakly to moderately to strongly nonmetallic character.

(vii) These increasing degrees are consistent with the literature:
 * "As one examines the elements…a progression is observed from slightly nonmetallic to strongly nonmetallic and very active."
 * — The Physical Sciences: Inquiry and Investigation, Stafford DG, Renner JW & Rusch JJ 1977, Glencoe Press, Beverly Hills, p. 225

11. Yes, I adjusted the article to bring it more into line with DS's proposal to refer to "these" nonmetals. My reply along these lines occurs in the "Other nonmetals" and "nonmetals" section, just after Double sharp's opening post.

In conclusion, I've addressed all your concerns, by way of: Sandbh (talk) 01:52, 23 September 2021 (UTC)
 * previous updates to the article that addressed prior concerns raised by Double sharp;
 * addressing your misconceptions;
 * existing literature-supported or literature-consistent article content;
 * explaining my approach in the context of other wp content; and
 * updating the article per your good idea at #6. Sandbh (talk) 01:52, 23 September 2021 (UTC)

Tetrachotomy cont. (C)
I have yet to read your response closely, but what I've seen so far has been impressive and it gave me a different outlook on the matter. Thank you for giving me such a detailed response as it helped me realize better where you are coming from. I'll try to not keep you waiting for too long.--213.24.126.69 (talk) 12:38, 25 September 2021 (UTC)

1. I did see your response to DS, but thought it did not quite address my concern (which is mentioned later in this post). I do get the impression from time to time that while agreeing, your focuses are different from what I'd expect. I'll provide an example of that later in this post.
 * Length of your post. Yes, you were correct when you said it's easier to raise concerns than to address them. I do want to note that my participation in this peer review is also under these premises: there are no consequences for you to disagree with me here (unlike in an FAC), and perhaps people wouldn't be willing to take past concerns from an IP editor quite as seriously as from a username, so I am more free to speak my mind here without being afraid that I'll accidently damage your chances to get the star you're looking for. Mine is one opinion, and I'm glad it doesn't have more weight than it should. Rather, I think I can help you more if I don't feel restricted about what I can and cannot say. I am also grateful for your identification of my mistakes.

2-6. Your addition of the staircase line, along with your responses, does address my concern. That being said, I checked reference 99 that claims to provide an example of germanium being treated as a metal, and I did not see any reference of germanium being called a metal. Perhaps I didn't see something or there is an error in that citation? If this is indeed an error, could there be more errors?

7-8. Thank you for providing more examples of your tetrachotomy. This puts me at ease somewhat. Similarly, thank you for your paragraph eight.

9. On this occasion, however, I can't agree. First of all, I never compared the metal and nonmetal articles as a whole. What I did compare is their respective treatments of classifications, i.e. one particular aspect. I disagree with the statement that two articles cannot be compared in one particular respect because one is said to be to the FA standard and one is not; the former is not necessarily inferior in every aspect. I also disagree with the notion a picture such as the one in nonmetal holds the same weight as the table in metal, although I understand there can be no absolutely convincing argument for either position. The picture is asking for more attention that a table does, and the focus of the table, as I see it, is listing the metals rather than displaying a classification, as is the case with your picture, not to mention the fact the metal article does not (and rightly so, in my opinion, even it's not up to the FA standard in some other aspects) feature the hexachotomy, because the very fact of having such a classification (regardless of what categories are used) already puts too much emphasis on subdivisions, which are inevitably arbitrary, even in the sources.

10. I will merely point out that it appears to me that you took quite the liberty (based on what you just pointed out) to conclude that this is a good justification for a decisive categorization such as the one in the article, and I wouldn't take such a liberty myself. However, I stress that my objective is to help improve the article rather than to either be convinced or convince you, though I could elaborate if you're interested.

11. I think it's great you did.

Again, thank you for the response. I did not get to this in detail, but I found the part of your response about metalloids particularly enlightening.--213.24.126.69 (talk) 14:03, 25 September 2021 (UTC)

Sandbh reply to IP editor: It's rewarding for me to learn the range of your concerns has significantly narrowed. I recall this is a result of carefully reading and either explaining the basis for my editing decisions or making further edits in response.

2-6. Yes, thank you, reference 99 gives the wrong page number. It should be p. 510 rather than p. 590, now fixed. I expect there'll be errors elsewhere. Metalloid achieved FA in 2014 yet I still find errors in it from time to time.

7-8. As noted, it is not my tetrachotomy. It is the literature that speaks of the p-block elements in terms of metalloids; halogens and noble gases. That leaves H, C, N, O, P, S and Se. For example:


 * [1] "The elements of central biochemistry[10] fall into two distinct subsets. (i) The main group nonmetal bioelements H, C, N, O, P, S, Se make up the bulk of the biomass with largely structural roles. They originate deep in the mantle of the earth and form volcanic gases (H2, N2, CO2, CO CH4, NH3, H2O, SO2, H2S, H2Se, COS, HCN, CH3SH, P4O10. (ii) The transition metal bioelements (Fe, Co, Ni, V, Mo, W, Mn, Cu, Zn) occur in organisms only in trace amounts, with mostly catalytic functions. Together with the main group biometals Mg, Ca they form essentially stationary crustal minerals. These two classes of bioelements come into close encounter at volcanic-hydrothermal ﬂow sites in the presence of liquid water [11], cf. [12].


 * Four main group nonmetal bioelements (H, C, N, O) form the structural basis for biochemistry. They are involved in all biochemical reactions, each one with its unique roles, indispensable for life, down to the pioneer organism. Sulfur and its companion selenium have diverse biocatalytic and bioenergetic functions. They are projected into the pioneer organism. Phosphorus is indispensable in genetics and bioenergetics, but limited to phosphate group chemistry. It must have been acquired after the origin of life. Therefore, the pioneer organism is deﬁned prima facie by main group system H—C—O—N—S—Se."


 * Wächtershäuser G 2015, "From chemical invariance to genetic variability", in Weigand & Schollhammer (eds), Bioinspired Catalysis: Metal-Sulfur Complexes, Wiley-VCH, Weinheim, p. 6


 * [2] "Nonmetals (H, C, N, O, P, S, Se, halogens, noble gases) mainly compose our atmospheric and biospheric environment…"
 * Möller D 2019, Chemistry of the Climate System: Volume 1 Fundamentals and Processes, 3d ed., Walter de Gruyter


 * [3] "The light nonmetals H, C, N, O, P, S Se, are very largely trapped in kinetically but not thermodynamically stable molecules and polymers."
 * Proceedings of the Royal Society of London: Biological sciences 1981. Series B, Volume 213, p. 365

9. Bear in mind the metal article largely looks the way it does due to my edits. That is why I felt comfortable saying it and nonmetal could not be compared, and this extends to the smaller aspects of each article you were comparing.

10. Well, the article does not say nor imply the classification used is decisive. Your concern about the basis for categorization is something you've raised before, and I've made associated changes to the article to address this.

Specifically, the lede says:
 * "Different kinds of nonmetallic elements include, for example, (i) noble gases; (ii) halogens; (iii) elements such as silicon, which are sometimes instead called metalloids; and (iv) several remaining nonmetals, such as hydrogen and selenium."


 * "The distinction between different kinds of nonmetals is not absolute. Boundary overlaps, including with the metalloids, occur as outlying elements among each of the kinds of nonmetals show or begin to show less-distinct, hybrid-like, or atypical properties."

And this is from the Subclasses section:


 * "Approaches to classifying nonmetals may involve from as few as two subclasses to up to six or seven. For example, the Encyclopedia Britannica periodic table has noble gases, halogens, and other nonmetals, and splits the elements commonly recognized as metalloids between the "other metals" and the "other nonmetals";[77] the Royal Society of Chemistry periodic table shows the nonmetallic elements as occupying seven groups.[78]"

Note the link to the List of alternative nonmetal classes sub-article.


 * "From right to left in periodic table terms, three or four kinds of nonmetals are more or less commonly discerned.[n 16]"

The accompanying image:
 * shows that authors differ in which elements they classify as nonmetals;
 * distinguishes nonmetals that are moderate to strong oxidizing agents;
 * says the dividing line is fuzzy thereby showing there is no universally accepted distinction between metals and nonmetals.

Yes, please elaborate if you feel you have some remaining concerns. Sandbh (talk) 08:07, 26 September 2021 (UTC)

Tetrachotomy cont. (D)
IP editor 213.24.126.69: 9. Again, I am not suggesting the two articles are alike or not alike enough. I have suggested that the metal approach to one specific issue is preferable to the nonmetal approach, and it is worth imitating. To this moment, it remains unclear to me why exactly you disagree on this and where the difference comes from, and I did not get the answer from your response. Anyway, this is not to say "you're wrong" or something to that effect; I have made a statement, you have responded in a way you saw fit, and that's good as far as I am concerned. This is a peer review with no immediate consequences. Do what you believe to be right as long as you have considered the opinions suggested to you closely.

10. While I think that your impression is fine per se, I think it's not quite right for Wikipedia specifically, and since you provided your reasoning behind thinking otherwise, I will provide what I regard to be flaws in your thinking as far as Wikipedia is concerned rather than in general. I will tell you your thinking back, explaining how I understand it and supplying it with some commentary.

(i) The groups of halogens, noble gases, and metalloids have been known for a long time (I agree). Metalloids have been known to be more like nonmetals than metals chemically (let's go along with this for now, even though there are obviously other criteria to classify a chemical element as a metal or a nonmetal, such as physical properties).

(ii) This is a personal impression, and it is not a valid reasoning as far as Wikipedia is concerned. Wikipedia does not consider itself to be a reliable source. Not to mention, there were other classifications used for nonmetals historically in the WP scheme of things. I will make another reference to this WP table later.

(iii) I really don't like this argument for reasons I have stated above. One, this is not a conclusion the study itself makes; the study even chooses different categories to classify the elements. Seeing the clusters you do is your own conclusion that is not found in the source; in Wikipedia terms, that is called "original research." Two, while that was enough in itself to disqualify the argument by itself, the bigger problem is that we don't even understand at the moment what exactly the graph is showing. What does the horizontal axis show? What about the vertical axis? Does one want to make a conclusion based on that information? We don't know.

So you see, your arguments two and three, as I understand Wikipedia's rules, don't work for---I can't stress this enough---Wikipedia. That is not to say they can't work at all, which is not the conclusion that I'm making. They don't work here because of the local house rules.

Above, you used the word "misconception" to refer to some of my beliefs on this topic. After you pointed out those, I found you were correct in that I did not conceptualize some things consistently with how others do it. Could the same be the case for you here?

With this in mind, let us continue.

(iv) I can't help the feeling you've changed the meaning of what I said and then presented me with the idea that the conclusion of my words is actually different from the one I made. Metal parses a list of metals by subgroups and that's it, the subgroups don't emerge elsewhere in the article. I made it clear that was what I liked about the metal approach. The nonmetal article has a graph and subsections, something metal does not have. I'm opposed to having either of that here as I would have opposed to having it there. But this aside, let's see the actual content you put into this paragraph rather than the presentation and see if it is good.

"Indeed, using “natural” classes or clusters to organise information is consistent with the cognitive-load theory of breaking up information into discrete or more easily memorisable factors i.e., chunking of information, and helps with content processing." -- that is correct in general but not really applicable to the article. This statement would work if the article was discussing each of the individual elements, the numbers of which (more than twenty) is indeed too big to process without assistance. However, the article does not discuss individual elements, but rather their common characteristics, and the argument is not applicable here. This argument about the need of subgroups, in contrast, is applicable for the list of metals mentioned earlier. This argument equally works for the WP table created at the dawn of WikiProject Elements (if I understand its original purpose correctly): it was originally meant to help process the list of the elements (even if a two-dimensional list).

Unlike with paragraphs two and three, I can't say that the argument could potentially work in a different environment. The text would need to be drastically different to be applicable at all.

(v) Ashford makes no argument here about any particular subgroups of the nonmetals category.

(vi) In a similar fashion, you could discern different categories and make the same conclusion. For example, what you're saying here is equally correct for the classification the source you mentioned in (iii) uses, so there is no real argument why this classification should be preferred. This argument also does not advocate for using a classification within the set of nonmetals at all.

Then again, Ashford said, "we continue the classification by making use of the degree to which they show these properties." This sounds like something to be done by researchers, because when it is done by Wikipedia editors, it qualifies as original research.

(vii) Like above, this is equally correct for any other classification, including the one in the Nature article, and it is equally not a call for using a classification at all.

With this in mind, the only substantial argument for the purposes of Wikipedia that I see here is (i). The question now is, is (i) an argument strong enough to make a case for this classification?

The question I will ask to answer this is this: are these three categories well-known subclasses of nonmetals specifically? The answer I am leaning towards is no, because I have not seen many descriptions of the nonmetals that use these subclassifications to tell the story of nonmetals in the same way you're intending to do in this article. Many natural thinking here is that if the reliable sources don't do that, you shouldn't either. However, I stand open to correction on this on the account you may present to me some examples of classifications I'm not currently considering.

That's where I stand on this. As I promised, I will no longer stop you from starting the FAC. I will not respond unless you really want me to. From here, act as you see fit.--213.24.126.69 (talk) 12:08, 2 October 2021 (UTC)

And of course, best of luck with your upcoming FAC.--213.24.126.69 (talk) 12:09, 2 October 2021 (UTC)

Sandbh reply:

From the outset, I reiterate the following Items:
 * 1) The nonmetal article is focused on chemistry i.e. the lede starts, "In chemistry…".
 * 2) The article is about different kinds of nonmetals, rather than being about each of the nonmetals, or nonmetals in groups, such as pnictogen nonmetals or chalcogen nonmetals.
 * 3) We have separate articles for:
 * each nonmetal;
 * each group within which a nonmetal occurs;
 * List of alternative nonmetal classes;
 * Properties of nonmetals (and metalloids) by group;
 * Metalloids; halogens; and noble gases; and
 * CHON nonmetals.



*    *     *

(i) As you note, "there are other criteria to classify a chemical element as a metal or nonmetal". Yet each of them results in anomalies. For example, some count As and Sb as metals even though each of these have a predominately non-metallic chemistry.

Something similar happened when K and Na were isolated. It was suggested they be called metalloids since they floated on water, a physical property, whereas all other metals then known were a lot heavier. This proposal didn't get up since K and Na were found to behave chemically like nonmetals. On that basis (plus the fact that they looked like metals) they were admitted to the metal club.

Subsequently, the word metalloid came to be retained for arsenic and antimony, because they looked metallic, another physical property, yet behaved chemically like nonmetals. The funny thing is graphite, black P, selenium, and iodine also look like metals but are not called metalloids, except for Se in the environmental literature.

Ashford (pp. 289–290; 320) was of the view that the distinction between metals and nonmetals is not merely one of appearance and physical properties; it is deeper than that—it involves a distinction between the chemical properties of these two types of elements.

Anyway, there are a number of different ways to deal with metalloids and this is noted in the article:


 * "Since the metalloids occupy frontier territory, where metals meet nonmetals, their treatment varies from author to author. Some consider them separate from both metals and the nonmetals; some regard them as nonmetals[95] or as a sub-class of nonmetals;[96] others count some of them as metals, for example, arsenic and antimony due to their similarities with heavy metals.[97][n 19] Metalloids are here treated as nonmetals in light of their chemical behavior, and for comparative purposes."

(ii) My impression was informed by the relevant wp talk page archives of the time. Reading the archives confirmed no more than what I said. I do not rely on this history; I rely on what RS say, as cited in the nonmetal article. My point was only to note that my research, based on RS, confirmed their research (the wp editors at that time). For other classifications used for nonmetals in the WP scheme of things see Item 3(c).



(iii) Here is the image again:

The study instead chose to use the following classes: {metalloid}-{polyatomic nonmetal}-{diatomic nonmetal}-{noble gases}, which were the wp classes up to 2018. They were replaced by the {metalloids}-{reactive nonmetals}-{noble gases} trichotomy which evidently didn't provide the authors with sufficient fidelity.

In the Nature article, note the recognition of metalloids, and noble gases. It's a trivial exercise to then discern the four stable halogens, F, Cl, Br, I, which form a beautiful, closely packed, linear reef.

All that remains are H, C, N, O, P, S, Se. As the authors themselves note:
 * "Chemically similar elements are seen to cluster together and the overall distribution exhibits a topology reminiscent of the periodic table itself."

Thus, it's not me seeing the clusters as I do; two of them are acknowledged by the authors; the other two are right there in front of my eyes, with the halogens F, Cl, Br and I universally recognised in the literature, astatine being routinely ignored. There is no OR here.

As far as the axes are concerned, I did not inquire further given:
 * the authors concluded that the overall distribution exhibits a topology reminiscent of the periodic table itself;
 * the calibre of the journal involved, which is no less than Nature, and the rigorous screening which articles appearing in that journal undergo; and
 * the number of citations the article has rec'd since publication in 2019, now 353, up 26 in six weeks.

If it was good enough for the authors; the referees; the editor of Nature; and 353 citations, that would seem to be good enough for wp rules, noting the distribution involved was based on more than 3,000,000 citations.

I gather the graph is a 2D projection of a multi-dimensional space using principal component analysis, of which I know basically nothing about apart from the fact that it's a widely used and recognised mathematical technique.

As noted:
 * my argument (ii) is not something I'm relying on; and
 * the basis for argument (iii) is self evident, from the image shown above.

(iv) The nonmetal article discusses the shared characteristics of the clusters of nonmetals commonly found in the literature namely noble gases, nonmetal halogens, and metalloids. That leaves a bunch of unclassified nonmetals.

I don't follow your logic that chunking into logical clusters requires a discussion of the individual properties of each of the 23 nonmetals involved. Per Item 3d, the latter discussion is found in its own sub-article. Equally the metal article—the approach to which you prefer—divides the elemental metals into chunks yet does not discuss the individual properties of the metals involved.

(v) Ashford confirms is it OK, in a scheme of classification of natural objects, for there to be some overlaps between the classes. And that despite these overlaps it is OK to continue so classifying. This is noted in the article and is especially relevant to the post-transition metals, metalloids, and unclassified nonmetals.

Ashford refers to the following kinds of nonmetals: metalloids; halogens; and inert gases. He writes (p. 340):


 * "This order of the elements is the essence of Mendeleev’s discovery, which he called the periodic law. It may be stated as follows, "If the elements are arranged in the order of their atomic weights, from the lightest to the heaviest, a repetition of a sequence of properties is observed." The sequence is a stepwise change in properties from strongly metallic, to weakly metallic, to intermediate, to weakly nonmetallic to strongly nonmetallic, followed by an abrupt and complete, or almost complete, disappearance of all chemical properties. This sequence is repeated several times on going down the list until all the elements are exhausted."

He refers to the transition metals too.

There is an impressive obituary for Ashford, here and some more about him, here.

(vi) It is not so easy to discern a similar progression in nonmetallic character using other classes. For example, the progression from metalloids to reactive nonmetals to noble gases is too coarse; and a progression from metalloids, to polyatomic nonmetals, to diatomic nonmetals, to noble gases is clunky and contrived, and this scheme is rarely found in the literature. Recall that I came up with the {polyatomic}-{diatomic}-{monatomic} scheme, the adoption of which you did not support. I was the one who wrote the nonmetal article around that taxonomy. I remember how hard it was to get it to work, and expressed my regret about supporting that scheme later on.

There is no OR in metalloids, other nonmetals, halogens, and noble gases. All the information is set out in the literature, as cited.

(vii) It is less than accurate to say that increasing degrees of nonmetallic character are equally seen in any other classification, as I have outlined above. The {metalloids}-{reactive nonmetals}-{noble gases} taxonomy, which is not often seen in the literature, given the frequency with which the halogens are discussed separately, effectively hides information, and makes it harder to get an overall appreciation of the nonmetals.

The classes of metalloids, and noble gases are well-known. The class of halogens are well known, noting that the sizeable majority of texts focus on F, Cl, Br, I.

The article refers to the rest of the nonmetals as unclassified nonmetals as these have no widely recognised collective name. Accordingly, the unclassified nonmetals section in the Subclasses section of the article has just one paragraph about their shared properties, with 21 supporting citations.

Conclusion


 * Thank you for your participation in the PR.
 * Many improvements to the article ensued as result.
 * As per your closing thoughts I'll soon close the PR, and proceed to FAC. Sandbh (talk) 11:57, 4 October 2021 (UTC)

General nonmetal behaviour (cont.)
Sandbh reply to DS: Well spotted. Mention of interstitial compounds in the article should have read "interstitial or refractory", now fixed.

On catenation, the trihydrogen cation H3+ is thought to be one of the most abundant ions in the universe.

Since H3+ is featured in interstellar rather than terrestrial chemistry its catenative capacity could be said to be unconvincing. Yet that's not the point. Instead, as noted in the article, there's a spectrum of applicable properties in each class. C is the most prolific catenator. H happens to the poor cousin.

While it's essential that a periodic table displays important trends in element chemistry at ambient conditions we need to keep our eyes open for unexpected chemical behavior in near ambient, or unusual conditions. A combination of experimental data in ambient, near ambient, and unusual conditions, and theoretical insight, supports a more nuanced understanding of complex periodic trends and non-periodic phenomena.

In ambient or near ambient conditions there's more to H:
 * Theories of the structure of water involve three-dimensional networks of tetrahedra or chains and rings, linked via H bonding.
 * A polycatenated metal complex with rings linked by H bonds was reported in 2008.
 * In organic chemistry, H bonding is known to facilitate the formation of chain structures. For example, 4-tricyclanol C10H16O shows catenated H bonding between the hydroxyl groups, leading to the formation of helical chains; crystalline isophthalic acid C8H6O4 is built up from molecules connected by H bonds, forming infinite chains.
 * In unusual conditions, a 1-dimensional series of H molecules confined within a single wall C nanotube is expected to become metallic at a relatively low pressure of 163.5 GPa. This is about 40% of the ~400 GPa thought to be required to metallize ordinary H, a pressure which is difficult to access experimentally.
 * While N is a reluctant player, long chains have attracted considerable attention in the research field of propellants, explosives, and gas generants. The longest known chain stops at eleven; compounds having five-membered N rings have been known since 1956. LiN5 is a five-ring nitrogen compound, only recently synthesized.
 * O is well known in the form of ozone, as are the peroxides ╱O–O╱ and ozonides −O╱O╲O−. The simple H trioxide, H2O3, already proposed by Berthelot in 1880, was prepared in 1993 and found to be metastable below −40 C°. The tetroxide, H2O4 was suggested by Mendeleev in 1895 and characterized in 2011, below −125 C°.

O and Cl is an example of a diagonal relationship. There's a footnote in the article setting out these kinds of relationships. I'll see about adding this one. Sandbh (talk) 08:10, 14 September 2021 (UTC)

Re {N, S, I}. Among the other nonmetals, O is a strong oxidizer; N, S are somewhat; hobbled; and H, C, P and S are not noted for their capacity in this regard. This is another example of there being a spectrum of applicable properties in each subclass. As far as iodine goes, F, Cl, Br are noted as being strong oxidizers, whereas I is somewhat hobbled. It's sufficiently corrosive to cause lesions resembling thermal burns, if handled without suitable protection, and tincture of I will smoothly dissolve gold. That said, it's only a moderately strong oxidizing agent.

We seem to be heading into the question of how much more of this kind of detail could or should go into the article.

The thing about adding something about the quasi-metalic nature of H is that so much has been written about the peculiar nature of H that it would seemingly be quite hard to condense that down, as opposed to exploring it in the H article. More to follow. Sandbh (talk) 08:17, 14 September 2021 (UTC)

Unusual conditions
Double sharp post: Sure, in unusual conditions many things can happen. However, the categorisation is mostly based on Earthly conditions in the first place. Well, to aliens living on Jupiter's core, there are only two nonmetals: helium and neon. (Perhaps fluorine also, since no one has yet measured its metallisation pressure.) And to aliens living on Pluto, nitrogen is clearly a condensed substance of low boiling point, and water ice is clearly a strong high-melting solid, the stuff of mountains. I think that neither of these are what most chemists have in mind, and suggest that we keep that in mind when discussing interstellar molecules, where even weirder things can stick around because there is nothing for them to react with. :)

Also, it seems to me that rocket fuels are supposed to give you a whole lot of energy in a small box, which is why such entertaining substances as ClF3 were considered in that capacity. So pointing to rocket fuels to find nitrogen compounds with significant catenation is actually a good illustration that N is not too happy to catenate, because of the size of the boom that occurs when it abruptly stops catenating. Same story with explosives, and with gas generants (after all, probably nitrogen is one of the gases being generated) :) Finally, I hope we can agree that these short chains of nitrogen and oxygen, that are quite ready to abruptly revert to being N2 and O2, are extremely small potatoes compared to the catenation ability of carbon, which happily goes on for thousands of atoms at standard conditions with nary a complaint.

But let me put it this way. We agree that there is a spectrum with regard to nonmetallic properties. We also agree that the spectrum often cuts across the subclasses you're using. Oxygen is a stronger oxidant than iodine, and it's a lot more electronegative too, for example. This situation isn't quite like the situation with the noble gases (which are obviously very different), or the metalloids (which are sometimes included and sometimes not). If that's the case, though, why separate out halogens at all? They are clearly part of that spectrum that says nonmetallic character usually increases going up and to the right, unlike the noble gases which are clearly off doing something quite different (they do not really want more electrons, they just hold the ones they have tightly). It would avoid some of the awkward problems needed when finding a generalisation that suits oxygen as well as selenium in your "unclassified nonmetals" category, and also avoid the annoying astatine saga that really is a non-issue to pretty much everyone. Note, this is about clearer generalisation, rather than more detail: my current issue with calling out the halogens as a category is that it doesn't seem to always suggest the correct generalisation, because of the strength of nonmetallic character in nitrogen, somewhat sulfur, and especially oxygen. Double sharp (talk) 09:10, 14 September 2021 (UTC)
 * Sandbh reply: Yes, please feel free to sandbox a proposed version talking about general nonmetal behaviour instead (so they become stronger as you go to the top and the right side, to cover the nitrogen and oxygen issue).
 * Currently my feeling is that such content, which would presumably take more of helicopter view of the nonmetals, could nicely complement the existing approach.
 * Here are some comments on your other thoughts.
 * Yes, along the lines of chemistry on Pluto, Cao et al. wrote as follows:
 * "There is a long history in chemistry about substances and reactions regarded as possible or impossible, according to powerful stories in journals and text-books. They emerged because periodicity expectations and other theoretical models excluded, precluded or prescribed them, and they were advanced by earlier accidentally unsuccessful experimental efforts causing accepted narratives in the community. This is another example of how heavily empirical observations and non-observations are theory-laden in positive and negative senses."


 * Subsequently, several instance of impossible chemistry turned out to be possible, with the classic example perhaps being the supposed inertness of the noble gases.


 * As I recall you mentioned, the capacity of N and O to catenate is hampered by lone-pair repulsion that weakens the respective N−N and O−O bonds. In the case of O, a significant problem is that the bond energies of most atoms with O are substantially greater than bond energies to other like atoms, hence catenated compounds of the elements tend to be unstable to oxidation. But if the central atom is small, or other atoms—in the case of heterogenous compounds—are large, there may be sufficient steric hindrance to allow the approach of O or other reactive molecules and enable reasonable stability for catenation (Wulfsberg, Principles of Descriptive Inorganic Chemistry, pp. 202–207).


 * Certainly, the ability to catenate or self-link an element’s atoms and form chains and rings is rather marked among C, S, P and Se (in that order).


 * Ozone is a reasonable example of a relatively common catenated form of O. It is small potatoes compared to the catenative ability of C, yet I feel it is not to be sneezed at given its abundance, including in the Earth's ozone layer, and its many industrial and consumer applications related to oxidation.


 * The relative lack of stability of catenated N is the reason why long N chains have attracted considerable attention in the research field of propellants, explosives, and gas generants.


 * There are no substantially awkward problems to do with generalisations that suit O as well as S. For example, O and Se each have biogeochemical cycles, and exhibit luminal phenomena, and while O and N have well known roles in explosives, S and SE compounds, with a high N content, although less well known and explored, are somewhat energetic (Houlton, '"Boom!", Chemistry World, 2014, 4 Dec).


 * I have a reservation about the word "your" as in "your 'unclassified nonmetals' category". The "category" isn't mine; it's a bunch of elements left over after the nonmetals are parsed, in the literature, into noble gases, halogens, or metalloids. Since they have no widely recognised collective name, it seems apt to refer to them as unclassified nonmetals, an expression which feels more accurate and less clumsy than "other nonmetals". In a similar manner, the Ln were sometimes referred to as "unclassified elements", before their place in the periodic table was established. Likewise, Shoemaker (1895, p. 7) in his A Practical Treatise on Materia Medica and Therapeutics listed Fe, Ni, Co, Pt and Au as "unclassified metals" under the heading "Heavy metals".


 * I feel there's no annoying At saga given, as you say it really is a non-issue to pretty much everyone and even literature sources commonly ignore it, and say so, on account of its rarity and intense radioactivity, when discussing the halogens. Sandbh (talk) 02:28, 15 September 2021 (UTC)


 * Sandbh reply, PS: After calming down I've added a preliminary paragraph about the metallic and nonmetallic character of H, sans cites, in the unclassified nonmetals section. Sandbh (talk) 08:08, 15 September 2021 (UTC)
 * Now done, including cites. Sandbh (talk) 05:52, 16 September 2021 (UTC)

I will not be able to respond until next Monday at the very earliest. Just in case, I'm reminding you that you're free to abandon my review whenever you feel like it; I won't take any offense.--213.24.126.91 (talk)18:35, 16 September 2021 (UTC)
 * That's OK as I'm waiting for Double sharp too, with his sandbox proposal. Sandbh (talk) 23:32, 16 September 2021 (UTC)
 * I've added a footnote to the subclasses table explaining the thick bold line around {O, S; N; F, Cl, Br and I} as encompassing the moderate to strong oxidizing agents. Sandbh (talk) 07:25, 18 September 2021 (UTC)
 * The reason I've delayed a bit on the sandbox proposal is because you've been making some interesting changes that I like. :) I've started to think about it, though. Should be able to write something up soon. Double sharp (talk) 07:37, 18 September 2021 (UTC)

"Other nonmetals" and "nonmetals"
It seems that if the "other nonmetals" are not referred to as such, then they are referred to as "nonmetals". I had thought this was peculiar since it outwardly implies that e.g. halogens and noble gases are not nonmetals, whereas they most certainly are. In instances where {H, C, N, O, P S, Se} are called "nonmetals" rather than "other nonmetals", the halogens e.g. are regarded as a subset of nonmetals, and {H, C, N, O, P, S, Se} are nonmetals without a subset identity, if you get my meaning.

To the extent that IUPAC nomenclature is relevant, there is a further anomaly, pointed out by Rayner-Canham, that among the metals the only collective sets with a "metals" suffix are the alkali metals and the AEM. The Ln and An don't, for example.

I've added citations to examples of the "other nonmetals" and "nonmetals" labels—one of these is to a book edited by Eric Scerri, no less; and the LANL periodic table likewise calls them just "nonmetals". Sandbh (talk) 07:32, 19 September 2021 (UTC)
 * Yes, it's bizarre. So does the ACS table, BTW.
 * The way I had in mind to deal with them was to say that we had the noble gases and often also the halogens, and then that the remaining nonmetals exhibited a wide variety in classification; and then use words like "These nonmetals" to refer to them, something like "These nonmetals generally exhibit moderate nonmetallic tendencies" rather than "The unclassified nonmetals generally exhibit moderate nonmetallic tendencies". I think this accords with what you say about nonmetals without a subset identity. While acknowledging somewhere that, if it is to the author's taste, further subsets can be given to include them, e.g. nonmetal chalcogens (O, S, Se, Te) or biogens (CHNOPS). Double sharp (talk) 07:36, 19 September 2021 (UTC)

Sandbh on subsets: I forget to add it was LANL where I first saw the subset concept i.e., "The halogen elements are a subset of the nonmetals."

I like your suggestion about the remaining nonmetals, and how to refer to them.

There is a flavour of this in the article at the start of the Subclasses section, which says…
 * "Approaches to classifying nonmetals may involve from as few as two subclasses to up to six or seven"

…and later in the article where it says:
 * "Some or all of these nonmetals nevertheless have several shared properties. Their physical and chemical character is moderately non-metallic, on a net basis."

Going further along these lines, I've changed one of the lede paragraphs to now say:


 * "Different kinds of nonmetallic elements include, for example, (i) noble gases; (ii) halogens; (iii) elements such as silicon, which are sometimes instead called metalloids; and (iv) several remaining nonmetals, such as hydrogen and selenium. The latter have no widely recognised collective name and are hereafter informally referred to as "unclassified nonmetals". Metalloids have a predominately (weak) nonmetallic chemistry. The unclassified nonmetals are moderately nonmetallic, on a net basis. Halogens, such as bromine, are characterized by stronger nonmetallic properties and a tendency to form predominantly ionic compounds with metals. Noble gases such as xenon are distinguished by their reluctance to form compounds."

I added Roman numerals make the sentence more legible. The bolding marks some changes.

The Unclassified nonmetals section now says:


 * "They are generally regarded as being too diverse to merit a collective examination, and have been referred to as other nonmetals, or more plainly as nonmetals, alongside metalloids and halogens. Consequently, their chemistry tends to be taught disparately, according to their four respective periodic table groups, for example: hydrogen in group 1; the group 14 carbon nonmetals (carbon, and possibly silicon and germanium); the group 15 pnictogen nonmetals (nitrogen, phosphorus, and possibly arsenic and antimony); and the group 16 chalcogen nonmetals (oxygen, sulfur, selenium, and possibly tellurium). Other subdivisions are possible according to the individual preferences of authors.

Sandbh on metalloids as a subset of nonmetals(?): In the authors write:


 * "Duffus (2003) has argued that since toxicological properties of elements are determined by their chemical properties, therefore metalloids should not be considered as a subset of metals but rather as a subset of nonmetals."

Reading Duffus' IUPAC Technical Report I couldn't find explicit support for their assertion. However the following extracts caught my eye:


 * 1) "…there is a need to subdivide the metals into different chemical classes if we are to consider carefully their individual properties and safe use."
 * 2) "Terms that have been commonly used in specifying groups of metals in biological and in environmental studies are listed…The limitations of these terms are clear. They are arbitrary and imprecise. Several categories overlap, making them inexact."
 * 3) "Metalloid—See “semimetal”…Semimetal—An element that has the physical appearance and properties of a metal but behaves chemically like a nonmetal [Atkins & Jones 1997, Chemistry—Molecules, Matter and Change, 3rd ed., WH Freeman, New York]
 * 4) "If metallic elements are to be classified sensibly…the classification must relate logically…and each metal species and compound should be treated separately in accordance with their individual chemical, biological, and toxicological properties."

Perhaps the basis for their assertion was #3 and #4 given metalloids are, by logical deduction, not metals.

I hope all of that helps. Sandbh (talk) 07:20, 20 September 2021 (UTC)

Smaller comments
If you like, I could write down my smaller comments at a later time. I'd like to stress that I liked the article and I think it'll make a strong candidate for getting a bronze star once these are resolved.--213.24.127.60 (talk) 16:38, 22 August 2021 (UTC)
 * Sandbh comment: I'd like to learn of your smaller comments. Sandbh (talk) 00:42, 24 August 2021 (UTC)
 * I will bear this in mind. I apologize for not being able to respond quickly, and I'll try to have produced more responses by the end of the week. However, if at some point you find yourself too tired of waiting for me, feel free to abandon me and my review. I'll merely hope it was of any use to you, which is the point of this review in the first place.--213.24.133.229 (talk) 18:46, 25 August 2021 (UTC)
 * Sandbh comment: I'm happy to wait. Your thought provoking feedback represents welcome stress testing of the article and can only be a good thing for an FAC. Sandbh (talk) 23:42, 27 August 2021 (UTC)

Here comes the list of smaller comments. It will probably not be long, although it may be continued in the future.
 * The matter chart mentions physical separation, but it does not mention that pure substances can mix to yield mixtures.
 * Sandbh comment: Pure substances are on the left; mixtures are on the right. Sandbh (talk)


 * "Most nonmetallic elements have less stable allotropes" -- less stable than what? it too me some thinking and a few seconds to figure it out, which is something you should avoid asking you reader for.
 * Done. Copy edited accordingly. Sandbh (talk) 02:17, 31 August 2021 (UTC)


 * "The unclassified nonmetals are typically found in association with oxygen or sulfur." -- from what I read, this is correct but the impression I get after reading the list in the article is different from the one I get after reading this sentence. It would be fairer to say that all aforementioned elements are typically found in some combination with oxygen. Sulfur seems to bear little importance of its own, except for one other element it is located next to in the periodic table.
 * Done. Copy edited accordingly. Sandbh (talk) 02:17, 31 August 2021 (UTC)


 * "$1,636 per 20 ml, equivalent to ca. $860,000 per gram" -- I take it radon is not actually available in gram quantities, because it price per gram would be lower otherwise? If so, it would be nice to explain in a note.
 * Done. The passage now reads, "$1,636 per 0.2 ml unit of issue…(with no indication of a discount for bulk quantities)." I misread 0.2 ml for 20 ml so the price equivalent is in fact $86,000,000 per gram =:o Sandbh (talk) 02:17, 31 August 2021 (UTC)


 * "Applications in common" -- this seems a rather strange wording. Why not "Common applications"?
 * Done: Changed to "shared uses". Sandbh (talk) 02:17, 31 August 2021 (UTC)


 * The Discovery section seems far too short. You could at least mention how these elements were discovered, not just when.
 * Comment. Excellent suggestion. Sandbh (talk) 02:17, 31 August 2021 (UTC)
 * Done. Sandbh (talk) 08:20, 31 August 2021 (UTC)

The list is not long; feel free to assume its shortness is proof enough that I believe the article is in a good shape.--213.24.133.229 (talk) 16:11, 28 August 2021 (UTC)
 * Thank you! Sandbh (talk) 02:17, 31 August 2021 (UTC)

Oops
I was drafting a response in my sandbox but ended up posting an earlier draft I'd been working on here thinking I was saving the more developed draft in my sandbox. Consequently I was surprised to see my less-developed response here, together with your follow on comments.

I'll see about filling in anything I left out and considering your latest thoughts.

Sorry about any clumsiness, duplications or nuancing that may ensue. Sandbh (talk) 00:42, 24 August 2021 (UTC)

Improving subsection flow
I've tried to make the ebb and flow of this part of the review clearer by:
 * using the labels Sandbh: or Sandbh (n): (n'' = a, b, c…); and
 * making better use of horizontal rules to delineate subsection starts and ends. Sandbh (talk) 01:31, 29 August 2021 (UTC)

Nonmetal halogens to common halogens
After further consideration, the article now refers to F, Cl, Br and I as "common halogens" in accordance with the use of this term, in the literature, to refer to F, Cl, Br, I. It eliminates any controversy to do with "nonmetal halogens" or "halogen nonmetals". Sandbh (talk) 23:58, 23 September 2021 (UTC)

IP 213.24.133.229: DePiep's request with respect to the last section


(transferred to a new section by me; original formatting preserved)--213.24.133.229 (talk) 23:24, 28 August 2021 (UTC)

Thank you for the tip about WP:TALKO. I made sure to make this edit without breaking any rule (that I'm aware of) this time.

My suggestion would be to consider closely how you write what you do. For example, when you want to write something like "this section is illegible," consider replacing it (in your mind to begin with) with "this section is illegible for me" and see from there and how you should word what you want to say. If you can't understand it, why should be announced in a manner as if it had to be seen by everybody like it's everybody else's problem that had to be fixed? You were not a part of this discussion and were not particularly meant to be. The way discussion was going did not break any rule; I asked you to name such a rule and you didn't one that related to the way discussion was proceeding. The people who were having that discussion could figure out themselves whether it was illegible or not, and it wasn't there to be judged by others. With this in mind, I conclude nobody was obliged to change the discussion to address your concerns. Sure, you could still ask for help from others so that could help you get up to speed; of course, you could. However, since nobody had to aid you, if you really wanted help, it was in your best interest to phrase that request politely (a common practice among people these days), not starting off by criticizing the way the discussion (that you, again, were not a part of) was going.

So since you used the word request yourself, if that was a request to me, then I'm declining it: not only am I comfortable with the way this section I started is structured, I'm not going to yield to that kind of a request. (To be clear, had the request been made politely, the answer would likely be different, or at least certainly less categorical and more friendly in its wordings.) If it was a request to Sandbh, he can, of course, choose how to act for himself; however, I don't see why he would act differently from me.

I'm somewhat sorry to note that we got off to a bad start. I most certainly did not come here to have a conflict with you (or, for that matter, anyone else). I will write a suggestion to you in your talk page shortly to see if that could be achieved.--213.24.133.229 (talk) 23:24, 28 August 2021 (UTC)
 * When I added the hatnote, the section looked like . That is: (1) section title was out of pattern (it is common practice to use: "Commens by UserName/IP"; I see no improvement in changing this). (2) The "Two ideas" from the title were shown in six subsections. (3) The single original text (7k b) was split into a dozen of unsigned, undated text blocks (by adding answers mid-text). (4) As this moment, the "Two ideas" have an offspring of ten subsections and fifteen sub-subsections (with names like and  (sic)). I had and have every reason to comment on that. As for "Rules" IP asks for: one general rule is that one does not alter someone else's posts, especially not changing their content. By breaking up the text flow, it was is broken.
 * Then, IP is turning my suggestion into Bad Faith. I wrote "Please", "Request" without reservation or secondary intentions &mdash; as one can read. I note that IP writes "You were not a part of this discussion". Of course, that is not the way a discussion works. This is an open page, and I am free to contribute as I think best. The paternalising talk towards me is unneeded and offensive. Writing "sorry to note that we got off to a bad start" could be a perception of one (and out of the blue to me). I see no reason, and it has not been shown to me, to take my edits as personal as the IP does. Note that my hatnote was not addressed to an editor (and, as it happens, the problematic talkflow setup was not created by IP &mdash; which did not matter). As described here I still stand by my edits.
 * All in all, since I am not convinced of the "suggestions" and reproaches (unpacked from their BF-accusations) at all, and since no other editor has supported your post except by someone grinding the OP text into out of context snippets), I am free to ignore it completely. I am free to contribute to this page, including "your" sections. -DePiep (talk) 08:23, 1 October 2021 (UTC)

Double sharp 2
I think that starting a new section here is probably better for clarity, because so much has changed (and IMHO, for the better!) with this article since my first set of comments. :)

So here's a rather big one: could not the discussion about At, Cn, Ts, and Og be placed together with "Definition and applicable elements"?

Currently, Cn is in a footnote, whereas At, Ts, and Og are sandwiched together in a huge paragraph in "Subclasses". But it seems to me that all we really say there is about whether or not they are nonmetals: we never get to discussing how they would appear in the classes (and rightly, IMHO, since so little is known). So why not put them in "Definition and applicable elements"?

I suggest the following wording:

"There is no rigorous definition of a nonmetal. Broadly, any element lacking a preponderance of metallic properties such as lustre, deformability, good thermal and electrical conductivity,[n 2] can be regarded as a nonmetal. Some variation may be encountered among authors as to which elements are regarded as nonmetals.

The fourteen elements effectively always recognised as nonmetals are hydrogen, nitrogen, oxygen, and sulfur (4); the corrosive halogens fluorine, chlorine, bromine, and iodine (4); and the noble gases helium, neon, argon, krypton, xenon and radon (6). Up to a further nine elements can be counted as nonmetals, including carbon, phosphorus, and selenium; and the elements otherwise commonly recognised as metalloids namely boron; silicon and germanium; arsenic and antimony; and tellurium, bringing the total up to twenty-three nonmetals.

Difficulties are encountered with the extremely radioactive elements, since not enough of them have ever been obtained to clearly determine if they are metallic or nonmetallic. The fifth halogen astatine is often expected to follow the nonmetallic nature of its congeners, but there is some experimental evidence that it is metallic due to relativistic effects. Even stronger relativistic effects for the seventh period are expected to make tennessine and oganesson, the halogen and noble gas of that period, metallic or at least metallic-looking. Their expected effects on copernicium (the heavy analogue of mercury) vary strongly between predictions: some expect metallic mercury-like behaviour, whereas some expect noble-gas-like behaviour. In the absence of clear experimental evidence, these elements have been excluded from the article's scope.

Since there are 118 known elements as at September 2021, the nonmetals are outnumbered several times."

But, of course, there must be room for improvement. :) Double sharp (talk) 08:55, 6 September 2021 (UTC)


 * That was the missing piece in the puzzle, thank you! I’ve moved any and all content about At, Cn, Ts or Og into the "Definition and applicable elements" section, as you suggested. The finer points are now in two footnotes.


 * There is a new (exploded) lede image, which combines the IP editor's suggestion with the older intact image, with the latter moved into the "Definition and applicable elements" section. The lede image caption has been updated accordingly.


 * In the process of making these adjustments I recall there were some trimmings which I'll look to restore as footnotes. I'll check to see if there's anything I left behind about At etc.
 * Done. Sandbh (talk) 07:54, 8 September 2021 (UTC)


 * The article is now looking quite streamlined, thank you. Sandbh (talk) 03:45, 8 September 2021 (UTC)

Shouldn't the packing efficiency for At be noted as a prediction? Double sharp (talk) 13:55, 12 September 2021 (UTC)
 * Pending. Sandbh (talk) 08:21, 13 September 2021 (UTC)

Also, in File:PT blocks and 1st rows.png seaborgium (106) is given symbol Sb. It should be Sg: Sb is antimony. Double sharp (talk) 13:19, 13 September 2021 (UTC)

YBG re top image
Suggestions: YBG (talk) 15:57, 9 September 2021 (UTC)
 * 1) Remove the shadowed metals; they aren't germain. Alternately you could enclose them in boxes to show them as being offset from the metalloids but that seems messy.
 * 2) Use circled letters for the bullets
 * 3) Consider whether group and period numbers are germain to this pic or are distracting to the main point. If they aren't used in any references made to this pic, they should be removed. If they stay, consider encircling the period numbers as is sometimes done elsewhere on WP.
 * 4) Include any additional discussion of H in the note. I removed a bunch because it wasn't really needed for the caption, but some of what I removed might be profitably included in the note.
 * 5) ✅ Make sure the three bulleted items never wordwrap; maybe by using ubl or nowrap or both. Then you could un-terse-ify the bullet items that I condensed severely. Maybe my terseness was too terse, but maybe not. You be the judge.


 * Thanks YBG. More thoughts to follow.


 * In the meantime, I'm having some trouble with the "Most common non-metal oxidation states" table, and getting it to stay on the right. If my screen is to big the table kind of floats into the middle of page, adjacent to the "Some typical chemistry-based differences between nonmetals and metals" table. Is there a way to stop that? Thank you, Sandbh (talk) 07:55, 10 September 2021 (UTC)
 * Can't help right now .... I'm restricted to editing on my phone right now≥. YBG (talk) 15:30, 10 September 2021 (UTC)


 * The metals are there to give context, and to show the metal to nonmetal pattern in that part of the periodic table.
 * That’s done.
 * The group numbers need to stay as they’re used elsewhere.
 * Looks good.
 * Ditto. Sandbh (talk) 11:05, 10 September 2021 (UTC)
 * '''re #1 metals for context
 * If you want the metals there to give context, they need more than just a shadowy letter. Right now they aren't really helping. The exploding nature of your pic is not apparent wrt the metals.
 * I'd suggest enclosing them in boxes so they hang togetherand the exploding offset is apparent. This could be just an outline of the group. You could also show a ragged tear to indicate that the table is incomplete.
 * Another idea would be to show a complete but very small PT like an inset locator map. I think this would eliminate the need for metals in the main image, but you be the judge.
 * In the current form the shadow letters do not really provide context unless you already know the context which of course is not your intention.
 * Sandbh reply: The caption has been amended to say, "Nearby metals are shown for context." The context is elaborated in the rest of the article. Sandbh (talk) 03:37, 12 September 2021 (UTC)
 * re #2 circled letters
 * Why do you say "That's done"? I still see only circled numbers, not circled letters.
 * Sandbh reply: My bad. I thought about using letters, but I don't want to confuse the situation with the old school nomenclature of A and B groups. Sandbh (talk) 03:37, 12 September 2021 (UTC)
 * re #3 group/period numbers
 * Ok, leave them in. But your first mention of groups by number is quite a ways down in the article.
 * Sandbh reply: The image caption now says, "While hydrogen (H) is usually placed at the top of group 1, to the far left of the extract, it is is sometimes instead placed over F as is the case here."
 * Hence the need for group numbers. Sandbh (talk) 03:37, 12 September 2021 (UTC)
 * And did you consider circling or removing the period numbers? No big deal if you don't.
 * Sandbh reply: No. Sandbh (talk) 03:37, 12 September 2021 (UTC)
 * YBG (talk) 15:30, 10 September 2021 (UTC)
 * Please reconsider removing the group and period numbers in the lede graphic. You don't mention group numbers and period numbers until much later in the article, and by then you have another nearby graphic. These numbers are not needed in the lede graphic. YBG (talk) 03:47, 11 September 2021 (UTC)
 * Sandbh reply: Please see my comment about the H note in the caption. Sandbh (talk) 03:37, 12 September 2021 (UTC)

Sandbh: Situation report

 * The definition of a nonmetal in the lede has been streamlined to focus more on the chemistry involved. NFA.
 * I'm currently checking all citations for any missing links to references or orphaned references. Up to # 170 220 so far. While this is going on I'm not adding any new numbered references as opposed to saying "[citations?]". Done.
 * The only thing remaining thereafter is to check the list of references is in alphabetic order. Done
 * Check for w/links to add; nix duplicates. Done.
 * If there are no more comments from the IP editor, it'll be FAC round 2 time. Sandbh (talk) 03:59, 30 September 2021 (UTC)
 * You asked me to elaborate on one of my comments, so I am obliged to do that. I'll have done it by the end of Sunday, though I'll try to not keep you waiting that long. After that, you're free to react however you will and good to head for the FAC. If I haven't done it by then, feel free to not wait for me and go straight to the FAC.
 * I think the article is in a great shape, even if I disagree with your presentation in one regard.--2A00:1FA0:4A4:57AE:1047:224:4552:D8AE (talk) 13:45, 30 September 2021 (UTC)
 * Thank you. I'll wait to hear from you. Sandbh (talk) 06:30, 1 October 2021 (UTC)
 * I have responded above. Act as you will if you want to, and feel free to start the FAC.--213.24.126.69 (talk) 12:11, 2 October 2021 (UTC)

DePiep
Since the start of this PR, the article has thoroughly changed ([phttps://en.wikipedia.org/w/index.php?title=Nonmetal&type=revision&diff=1039872532&oldid=1036692865&diffmode=source]; 266 edits). Then, by breaking up lines-of-reasoning by interspersing isolated replies, the main questions may be evaded or unanswered. Incidentally, I was brutally "forbidden" to reply to one, now large section. I don't think the mainline questions are answered. Note that, also because the versions differ hugely within every few weeks and because issues were raised elsewhere & before, making the lineup of issues I still see might take some time. -DePiep (talk) 16:18, 4 October 2021 (UTC)
 * Sandbh reply:
 * The article has thoroughly changed in response to the comments of peer reviewers, as it should.
 * The last contribution to this page that addressed the nonmetal article occurred over two weeks ago, as made by Double sharp on Sep 19th.
 * I addressed Double sharp's comments.
 * The only other contributions to this page, since DS' contribution on Sep 19th, and that addressed the nonmetal article have been by the IP editor and myself.
 * The IP editor has concluded their comments, as you can read from their last comments.
 * After their conclusion I wrote: "As per your closing thoughts I'll soon close the PR, and proceed to FAC. Sandbh (talk) 11:57, 4 October 2021 (UTC)"
 * This is what I will now do. Sandbh (talk) 04:22, 5 October 2021 (UTC)