Talk:Nonmetal/Archive 2

Color and state of matter
DePiep raises an interesting point.

Obviously all metals are shiny and all bar Hg are solid. I know a little about the shininess; visible light gets scattered by the delocalised surface electrons.

The nonmetals are shiny (B, Si, Ge, As, Sb, Te; C, black P, Se, I), colored (S, F, Cl, Br) or colorless (H, N, O, and the noble gases).

The mechanism of shininess for the semimetals C, As and Sb is the same as that for the metals.

The mechanism for the rest of the shiny nonmetals, which are all semiconductors, arises from their band gaps being less than equal to the visible spectrum cut off of 1.8 eV. S has a bigger band gap, giving rise to its yellow color.

The mechanism for the remaining colored and colorless nonmetals, has to do with the permitted energy levels that their individual electrons occupy.

Why metals are nearly all solid whereas nonmetals cover all three bases is something I'll need to look further into. I do know that Hg is liquid on account of relativistic effects.

Par for the course, there is a little bit of overlap going on here in that C, As, Sb have the electronic structure of semimetals, as does Bi. Yet the chemistry of C, As, Sb is largely nonmetallic whereas Bi is regarded as having just enough metallic character to merit being admitted to the metal club. Frex, nitric acid gives carbon dioxide with C, arsenic acid with As, antimony trioxide with Sb, and bismuth nitrate with Bi.

I intend doing this work as a stand alone exercise from John's copyediting, and will post the results here. Sandbh (talk) 05:18, 2 October 2022 (UTC)


 * TL;DR. If this is the missing encyclopedic link, it should be in the article. Then, I don't think it has the right proportions. As talkpage post, it doesn't solve the question. DePiep (talk) 06:50, 7 October 2022 (UTC)
 * Well in my favourite counterexample to that, sulfuric acid already gives the sulfate with Sb as well as Bi (but not As). To some extent it can be national-traditional variation: from what I remember, Russian authors are likelier to call Sb a metal than English authors (though this may be because Russian authors often don't recognise a "metalloid" category).
 * Metals are nearly all solid because the metallic bond is strong and, crucially, extends over the whole network. You really need special circumstances to have a liquid metal: few electrons to share (Rb, Cs, Fr), relativistic pseudo-closed shell configurations (Hg, maybe Cn and Fl), or some weird molecular-like thing going on (Ga). (And here I am assuming 40°C weather to define "liquid".) When the covalent bonds extend over the whole network, we always get a solid, too (B, C, black P, Si, Ge, Se, Te), and sometimes we even get one where it doesn't when van der Waals forces are strong enough (the big ones: white P, S, yellow As, red Se, I). So it's not a metal vs nonmetal thing; it's closer to a giant-structure vs molecular thing (blurring as the molecule gets heavier). Double sharp (talk) 22:36, 9 October 2022 (UTC)

Antimony does not really give a sulfate. Solid antimony sulfate contains infinite ladders of SO4 tetrahedra and SbO3 pyramids sharing corners. It is often described as a mixed oxide, Sb2O3.3SO3. Sandbh (talk) 03:00, 11 October 2022 (UTC)


 * If this is your objection to Double sharp's post, that means the rest is a good replacement for the color & phase topic in the article, starters. IOW, this is the encyclopedic approach (some ce todo allright). It also leads to the conclusion that it is not 1st-sentence-worthy. DePiep (talk) 08:19, 12 October 2022 (UTC)


 * This is a bad draft of the colour paragraph:
 * "Nonmetallic elements are either shiny, colored, or colorless. For graphitic carbon, black phosphorus, arsenic, antimony, selenium and iodine their structures feature varying degrees of delocalised electrons that scatter incoming visible light, resulting in a shiny appearance (Wiberg 2001, p. 416). The colored nonmetals (sulfur, fluorine, chlorine, bromine) absorb some colours (wavelengths) and transmit the complementary colours. For chlorine, its "familiar yellow-green colour...is due to a broad region of absorption in the violet and blue regions of the spectrum" (Elliot 1929, p. 629).^ For the colorless nonmetals (hydrogen, nitrogen, oxygen, and the noble gases) their electrons are held sufficiently strongly such that no absorption occurs in the visible region of the spectrum, and all visible light is transmitted.”


 * ^ The absorbed light may be converted to heat or re-emitted in all directions so that the emission spectrum is thousands of times weaker than the incident light radiation.


 * Elliot A 1929, "The absorption band spectrum of chlorine", Proceedings of the Royal Society A, vol. 123, no. 792, pp. 629–644
 * Wiberg N 2001, Inorganic Chemistry, Academic Press, San Diego. Wiberg is here referring specifically to iodine.


 * The difference in solid, liquid or gaseous forms of nonmetals is addressed in the Physical properties section, i.e. "The internal structures and bonding arrangements of the nonmetals explain their differences in form...".


 * — Sandbh (talk) 06:45, 21 October 2022 (UTC)

I've added a paragraph to the Physical section on the colours of nonmetallic elements. Could you please check to see if that looks OK? (The accompanying footnote needs a citation but the rest should be OK.) Thank you, Sandbh (talk) 12:33, 23 October 2022 (UTC)
 * It looks pretty much alright to me, based on what I could find in the literature. Double sharp (talk) 19:42, 29 October 2022 (UTC)

RfC on the Classification of elements
Over at WT:ELEMENTS an RfC is opened on the topic highly relevant on the nonmetals too. See. You are invited to participate. DePiep (talk) 07:23, 17 February 2023 (UTC)

Article could be revised and renamed: Main Group Chemistry
The article is nice, although the topic called Main Group chemistry might be more appropriate. Has that idea been discussed? --Smokefoot (talk) 22:25, 11 April 2023 (UTC)


 * Ealier discussion: WT:CHEM . Could be that Main Group is a valid topic, but I do not see how it would be an alternative for this topic. That is, replacing nonmetal chemistry. (Incidentally, does it differ from main group?) DePiep (talk) 06:29, 12 April 2023 (UTC)
 * Good point. You are correct: Nonmetal is a thing. The article is essential.  But the chemistry stuff (reactions, structures, minerals) should mostl be in Main Group Chemistry.
 * Yes, I realize that I am discussing this issue in two places, but I dont think that anyone at the Chem Project cares.--Smokefoot (talk) 20:08, 12 April 2023 (UTC)
 * No problem, Smokefoot, I only added the link to keep the arguments, already made, at hand. I assume this talkpage is best place. DePiep (talk) 06:19, 13 April 2023 (UTC)

Nonmetal halogen, halogen nonmetal
Both terms are found in the literature.

Since there are alkali metals, alkaline earth metals, and transition metals,  i.e. the convention is to put "metals" last, I've replaced mentions of "nonmetal halogens" with "halogen nonmetals". --- Sandbh (talk) 08:24, 24 April 2023 (UTC)

Astatine
Isn't astatine a metalloid? Here it says astatine is a metal, but most other sources say it's a metalloid or nonmetal? 2603:6000:8740:54B1:21BE:C597:B635:6023 (talk) 17:33, 26 February 2023 (UTC)


 * In lists of metalloids, astatine appears about 40% of the time.


 * The bulk properties of astatine remain unknown as a visible quantity of it would immediately self-vaporize from the heat generated by its radioactivity. It remains to be seen if, with sufficient cooling, a macroscopic quantity could be deposited as a thin film. Historically, "since elements in heavier periods often resemble their n+1 and n−1 neighbours more than their lighter congeners, astatine…was expected to be radioactive and metallic like polonium."[1]


 * Qualitative and quantitative assessments of its status, including having regard to relativistic effects, have been consistent with it being a metal:


 * 1940. Astatine was judged to be a metal when it was first synthesized.[2] That assessment was consistent with some metallic character seen in iodine,[3] its lighter halogen congener.


 * 1972. Batsanov calculated astatine would have a band gap of 0.7 eV[4] (but see the 2013 entry)


 * 1983. Edwards and Sienko speculated that, on the basis of the non-relativistic Goldhammer-Herzfeld criterion for metallicity, astatine was probably a metalloid.[5] As the ratio is based on classical arguments[6] it does not accommodate the finding that polonium (cf. 2006 entry following) adopts a metallic (rather than covalent) crystalline structure, on relativistic grounds.[7] Even so it offers a first order rationalization for the occurrence of metallic character amongst the elements.[8]


 * 2002. Siekierski and Burgess presumed astatine would be a metal in the context of some of the properties of iodine.[9]


 * 2006. Restrepo et al., on the basis of a comparative study of 128 known and interpolated physiochemical, geochemical and chemical properties of 72 of the elements, reported that astatine appeared to share more in common with polonium (a metal) than it did with the established halogens and that, “At should not be considered as a halogen."[10] In so doing they echoed the 1940 observation that, "The chemical properties of the unknown substance are very close to those of polonium."[11]


 * 2010. Thornton and Burdette observed that "Since elements in heavier periods often resemble their n+1 and n-1 neighbours more than their lighter congeners, eka-iodine [astatine]...was expected to be radioactive and metallic like polonium." [12]


 * 2013. Hermann, Hoffmann, and Ashcroft predicted At would be an fcc metal, once all relativistic effects are taken into account, and that it would have a band gap of 0.68 eV (cf. Batsanov) if only some of these effects were taken into account.[13]


 * While astatine could reasonably be presumed to be a metalloid based on ordinary periodic trends, relativistic effects—as seen in gold, mercury, and the heavier p-block elements—are expected to result in condensed astatine being a ductile FCC metal. It could also be expected to show significant nonmetallic character, as is normally the case for metals in, or in the vicinity of, the p-block.


 * The suggested distinguishing criteria for metals and nonmetals place At in a metal quadrant.


 * References
 * 1. Thornton BF & Burdette SC 2010, “Finding eka-iodine: Discovery priority in modern times”, Bulletin for the History of Chemistry, vol. 25, no. 2, pp. 86−96


 * 2. Vasáros L & Berei K 1985, General properties of astatine, in Kugler HK & Keller C (eds), Gmelin Handbook of Inorganic and Organometallic chemistry, 8th ed., At, Astatine, system no. 8a, Springer-Verlag, pp. 107–28 (109)


 * 3. Moody B 1991, Comparative Inorganic Chemistry, 3rd ed., Edward Arnold, London, p. 303


 * 4. Batsanov SS 1971, Quantitative characteristics of bond metallicity in crystals, Journal of Structural Chemistry, vol. 12, no. 5, pp. 809–813 (811).


 * 5. Edwards PP & Sienko MJ 1983, On the occurrence of metallic character in the Periodic Table of the Elements, Journal of Chemical Education, vol. 60, no. 9, p. 692


 * 6. Edwards PP 1999, Chemically engineering the metallic, insulating and supercon-ducting state of matter, in Seddon KR & Zaworotko M (eds), Crystal Engineering: The Design and Application of Functional Solids, Kluwer Academic, Dordrecht, p. 416


 * 7. Encyclopedia of the Structure of Materials, Elsevier, Oxford, p. 142; Pyykkö P 2012, Relativistic effects in chemistry: More common than you thought, Annual Review of Physical Chemistry, vol. 63, p. 56


 * 8. Edwards PP & Sienko MJ 1983, On the occurrence of metallic character in the Periodic Table of the Elements, Journal of Chemical Education, vol. 60, no. 9, p. 695


 * 9. Siekierski S & Burgess J 2002, Concise Chemistry of the Elements, Horwood Press, Chichester, p. 122


 * 10. Restrepo G, Llanos EJ & Mesa H, Topological space of the chemical elements and its properties, Journal of Mathematical Chemistry, vol. 39, p. 411


 * 11. Corson DR, MacKenzie R & Segrè E 1940, Possible production of radioactive isotopes of element 85, Physical Review, vol. 57, p. 459


 * 12. Thornton BF & Burdette SC 2010, Finding eka-iodine: Discovery priority in modern times, Bulletin for the History of Chemistry, vol. 35, no. 2, p. 86


 * 13. Hermann A, Hoffmann R & Ashcroft NW 2013, Condensed Astatine: Monatomic and metallic, Physical Review Letters, vol. 111
 * — Preceding unsigned comment added by Sandbh (talk • contribs) 03:22, 25 April 2023 (UTC) — Preceding unsigned comment added by Dhtwiki (talk • contribs)
 * To deconfuse. Currently this article makes this top level distinction: Metal-Nonmetal only. So, no major class Metalloids in there. The Metalloids appear as subdivision of class Nonmetals. The article is rewritten this way by Sandbh, with the pre-overhaul GA-icon kept undiscussed.
 * So the OP Isn't astatine a metalloid? (i.e., not a Metal), in this class scheme requires redefinition of At as a Nonmetal first before it can be subclassified Metalloid. Recent complication: same author (Sandbh) appears to have changed the article object (ie, everything) as "chemically" only while not changing anything to article body, title, TOC or setup???. This is disputable, in various ways, and is disputed. DePiep (talk) 08:41, 25 April 2023 (UTC)

Thank you DePiep.

Yes, the two great classes are (i) metals and (ii) nonmetals. This is a universal distinction. "Metalloids" is only a sometimes classification.

The treatment of elements occupying the frontier territory where the metals meet the nonmetals varies from author to author. Some consider them separate from both metals and nonmetals (and refer to them as metalloids); some regard them as nonmetals or as a sub-class of nonmetals. Other authors count some of them as metals, for example arsenic and antimony, due to their similarities to heavy metals. It has been known for over 100 years that the elements commonly recognised as metalloids (B, Si, Ge, As, Sb, Te) behave chemically like nonmetals. The article treats them as "metalloid nonmetals" in light of their chemical behavior, and for comparative purposes. The metalloids further meet the criteria for nonmetals of low density and relatively high electronegativity.

Astatine has at various times been counted as a metal, metalloid, or nonmetal.

It isn't included in the article since it has been counted as a (post-transition) metal. The article says:
 * "Astatine, the fifth halogen, is often ignored on account of its rarity and intense radioactivity;[17] theory and experimental evidence suggest it is a metal."[18]

The edit in question changed the opening sentence from:
 * "In chemistry, a nonmetal (or non-metal) is a chemical element..."
 * TO
 * "A nonmetal (or non-metal) is a chemical element..."

There was no change to the article object, since nonmetals are still referred to in terms of physical and chemical properties. Sandbh (talk) 06:39, 27 April 2023 (UTC)

Hatnote "In chemistry"
Added hatnoting "This article is about nonmetal elements in chemistry" is confusing, sloppy and not correct.

For starters, the body and the TOC say otherwise (eg "Physics"); this distinction is not made. Further hatnote specs (astronomy, metallicity, nonmetallic substances, in physics, valence and conduction bands) add to the confusion/mistake. If article content is changed into this, the article should be moved. But morte likely this is inappropriate application of hatnote; more like trying to fit topic description (lede issue) in a WP:HATNOTE.

I request and expect starts a talk on this page proposing all desired changes coherently. DePiep (talk) 06:27, 24 April 2023 (UTC)


 * Thanks DePiep for your interest. I followed WP:HAT in adding the hatnote.


 * The only other mention of "physics" is in the Discovery section of the main body of the article, which says:


 * "Chemistry- or physics-based techniques used in the isolation efforts were spectroscopy, fractional distillation, radiation detection, electrolysis, ore acidification, displacement reactions, combustion and heating; a few nonmetals occurred naturally as free elements."


 * This does not have anything do with the concept of a nonmetal in physics.


 * Astronomy and materials science are not mentioned in the main body.

--- Sandbh (talk) 07:14, 24 April 2023 (UTC)


 * Name change I'm inclined to change the name of the article to "Nonmetal (chemistry)" and to create disambiguation links for:


 * Nonmetal (astronomy) --> Metallicity
 * Nonmetal (physics) --> Valence and conduction bands


 * The hatnote would be reduced to "For nonmetallic substances see Materials science."
 * Sandbh (talk) 01:13, 28 April 2023 (UTC)

I've renamed the article to Nonmetal (chemistry) and trimmed the hatnote, after setting up redirects for Nonmetal (astronomy) and Nonmetal (physics). --- Sandbh (talk) 07:26, 30 April 2023 (UTC)

List of miscellaneous items
So, taking a dive in this article, specifically this version:
 * "largely make up the" I know this is shortest, but would "make up most of the" be a bit sounder grammatically? Done
 * "namely boron; silicon and germanium; arsenic and antimony; and tellurium" might work better as a parenthetical. Done
 * Footnote 6 I think "both metals" is better than "metals both" Done
 * I know, hypocritical from me but the "Physical" section could benefit from less instances of "occurs" Done
 * "as used in non-stick coatings for pans and other cookware." is unreferenced. Done
 * "From right to left in periodic table terms, three or four kinds of nonmetals are more or less commonly discerned. These are: the relatively inert noble gases;" are also unreferenced. Done
 * "Metalloids are here treated as nonmetals in light of their chemical behavior, and for comparative purposes." is unreferenced. Done
 * "In 2014 it was reported that the Earth's core" sounds a bit like a WP:PROSELINE thing; can it be reworded to be less time-dependent? Done
 * "Dingle explains the situation this way:" who is this Dingle? Done
 * "Oxygen is found in the atmosphere; in the oceans as a component of water; and in the crust as oxide minerals." lacks a reference. Done
 * I don't think that having a "daily cost" item is a good idea. I doubt that such prices are stable enough that they could be kept up-to-date with reasonable effort.
 * I rechecked the costs as at April 2023 since I did this originally as at August 2022. In the ensuing eight months there was hardly any variation, in relative terms. I suspect that an annual check would suffice, an idea I got from you. Sandbh (talk) 08:20, 3 May 2023 (UTC)


 * "Chemistry- or physics-based techniques used in the isolation efforts were spectroscopy, fractional distillation, radiation detection, electrolysis, ore acidification, displacement reactions, combustion, and heating; a few nonmetals occurred naturally as free elements." lacks a reference. Done
 * "Physical properties apply to elements in their most stable forms under ambient conditions, and are listed in loose order of ease of determination. Chemical properties are listed from general to descriptive, and then to specific. 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. Metals are included as a reference point." lacks a reference. Done
 * What is the source for the ionization energies in the comparison table? Done
 * Footnotes 4, 12, 13, 26 need a source Not applicable
 * Note 4 does not need a cite since it is only listing the grayed-out elements in the parent image; ditto note 12 sets out the first row elements in the parent image; note 13 as per note 4; note 26 is a meta-explanation of what is going on in the sentence.


 * Footnote 14 lacks a reference for one sentence Not applicable
 * That is an introductory and explanatory sentence; the cites are in the following three sentences/paras.


 * Footnote 23 has the somewhat mysterious "combined with sulfur" Done

I can do a source spot-check if so desired. Jo-Jo Eumerus (talk) 09:30, 2 May 2023 (UTC)


 * Tx JJ for this impressive list. I count 17 items, nine of which are for missing references. More refs should be no problem. The remaining eight items should be OK to address.


 * A source spot check was completed in one of the more recent FAC nominations by, as I recall, Complex rational.
 * --- Sandbh (talk) 07:35, 3 May 2023 (UTC)
 * All items have now been addressed. Sandbh (talk) 13:32, 3 May 2023 (UTC)

First paragraph of lede
The first paragraph of the lede starts by explaining what nonmetals are not:


 * "A nonmetal (or non-metal) is a chemical element that generally lacks a predominance of metallic properties; they range from colorless gases (like hydrogen) to shiny solids (like carbon, as graphite). They are usually poor conductors of heat and electricity, and brittle or crumbly when solid, due to their electrons having low mobility. In contrast, metals are good conductors and most are easily flattened into sheets and drawn into wires since their electrons are generally free-moving. Nonmetal atoms tend to attract electrons in chemical reactions and to form acidic compounds."

I am thinking about changing this so that nonmetals are instead explained in terms of what they are:


 * "A nonmetal is a type of chemical element that is a poor electrical conductor or is a mechanically weak and brittle solid the most stable oxide of which is acidic. They range from colorless gases (like hydrogen) to shiny substances (like carbon, as graphite). Their electrons have low mobility. In contrast, metals are good conductors and most are easily flattened into sheets and drawn into wires since their electrons are generally free-moving. Nonmetal atoms tend to attract electrons in chemical reactions and and to form acidic compounds."

The reference to poor electrical conductivity applies to nearly all nonmetals. Carbon, as graphite, is an exception. But it is a mechanically weak and brittle substance, and CO2 is an acidic oxide.

Among the metals, and semimetals (in a physics-based sense), gallium, arsenic, antimony and bismuth are brittle and mechanically weak. Gallium trioxide is amphoteric; aqueous solutions of arsenic trioxide are weakly acidic; antimony trioxide is amphoteric, but has acidic properties predominating; and bismuth trioxide is basic.

--- Sandbh (talk) 02:23, 28 April 2023 (UTC)
 * Well, how do the sources typically define things?
 * It seems to me that nonmetallicity is more correlated with keeping one's own electrons than attracting others', i.e. electronegativity rather than electron affinity. The noble gases are a clear example. Also, Cs has a higher electron affinity than B. Electronegativity is also not perfect considering that Au beats Si by this measure, but at least it doesn't have literally alkali metals beating nonmetals, but the noble metals. Double sharp (talk) 10:41, 28 April 2023 (UTC)

The sources are about 50:50 between defining nonmetals as (i) elements either not having the properties of a metal or (ii) in terms of more specific properties as per following 20 examples from the literature:


 * 1) …a substance that conducts heat and electricity poorly, is brittle or waxy or gaseous, and cannot be hammered into sheets or drawn into wire. Nonmetals gain electrons easily to form anions.
 * 2) A nonmetal is an element whose atoms tend to gain (or share) electrons.
 * 3) A nonmetal is a chemical element that is mechanically weak in its most stable form, brittle if solid, and usually gains or shares electrons in chemical reactions.
 * 4) As a result of the free electron, graphite, though a nonmetal, is able to conduct electricity while diamond cannot.
 * 5) The distinctive chemical property of a nonmetal is the ability to gain electrons to form an anion when reacting with a metal. The nonmetals have large ionization energies and most have negative electron affinities.
 * 6) If the oxide of a nonmetal is placed in water, the mixture will be acid.
 * 7) The simplest way to tell a metal from a nonmetal is that most nonmetals do not conduct thermal energy or electricity.
 * 8) nonmetals are insulators, with a few rare exceptions.
 * 9) A nonmetal is an element that gains or shares electrons when it combines chemically. There is no set of physical properties that applies to all nonmetals, there is for the metals.
 * 10) A metal is a lustrous malleable element that is a good conductor of heat and electricity; a nonmetal is an element that is a poor conductor.
 * 11) A nonmetal is an element that tends to gain valence electrons in chemical reactions, becoming an anion in the process.
 * 12) Chemically, the property of an element that makes it a nonmetal is the element's ability to gain electrons.
 * 13) A nonmetal is an element that usually has a low density, a low melting point, and is a poor conductor of heat and electricity.
 * 14) A nonmetal is an element that is relatively easily reduced.
 * 15) A nonmetal is a kind of matter that does not have a metallic luster, is a poor conductor of heat and electricity, and when solid, is a brittle material that cannot be pounded or pulled into new shapes.
 * 16) A nonmetal is one of a number of elements, including gases, liquids and solids, which are grouped together because they do not conduct heat or electricity well, are not ductile and malleable, and do not reflect light well. Chemically, nonmetal atoms form negative ions.
 * 17) Bands in metals In terms of the band theory, the distinction between a metal and a non-metal is that in the former there are incompletely filled bands.
 * 18) the principal chemical property of a non-metal is its ability to form a negatively charged anion by accepting electrons from a metal.
 * 19) A non-metal is an element which ionizes by electron gain.
 * 20) A non-metal is an element that has four or more valence electrons.

The properties include poor conductivity; brittle and mechanically weak if solid; usually low density and mp; large ionization energy; gain or share electrons; usually negative EA; form negative ions; acidic oxides. --- Sandbh (talk) 02:54, 29 April 2023 (UTC)

I've updated the lede paragraph to refer to what nonmetals are, rather than what they are not. Sandbh (talk) 07:22, 30 April 2023 (UTC) I found a hybrid nonmetal entry by Read J 1965, in JR Newman (ed.), The International Encyclopedia of Science, Thomas Nelson and Sons, London, p. 832:


 * "NONMETALS stand apart from METALS in many ways, both physically and chemically, although these two classes of elements merge into one another. Physically, nonmetals do not exhibit luster or polish; they are poor conductors of heat and electricity; if solid, they are often brittle, they are not ductile, and they possess poor tensile strength. At ordinary temperatures some are solid, some liquid, and some gaseous: their melting points range from −272°C(−457.6°F), under 26 atm pressure, for helium, to above 3550°C (6422°F) for carbon. Their values for specific gravity are low, compared with those for metals. Chemically, their oxides usually react with water to form acids, and their chlorides are often decomposed by water."

It is a good effort but not without errors.

That "nonmetals do not exhibit luster or polish" is contradicted by graphitic C, black P, gray Se, and I. That they are, "if solid...often brittle" is not quite true since all solid nonmetals are brittle, unless he had white P in mind which can be cut with a knife however black P, which is brittle, is the most stable form. That they are "poor conductors of heat and electricity" is contradicted by graphitic C. While Read says that "some" are liquid, bromine is the only liquid nonmetal.

--- Sandbh (talk) 02:39, 1 May 2023 (UTC) I restored the lede paragraph back to saying what nonmetals aren't since there is no agreement as to what they are. Sandbh (talk) 07:49, 1 May 2023 (UTC)


 * Perhaps you could say "Nonmetal is a classification of elements. It commonly refers either to or "? If there is more than one common definition of nonmetal, mentioning all of them would be better than implying there is only one accepted definition. Jo-Jo Eumerus (talk) 09:58, 1 May 2023 (UTC)

Simplifying the lede
I've adjusted the lede paragraph, and made associated edits later in the article, to make things easier to follow in terms of what is a nonmetal in the broadest sense of the term.

While there is no common rigorous definition of a nonmetal in terms of the precise properties involved, a broad definition based on relatively low density (a physical property) and relatively high electronegativity (chemical) encompasses: Mention of the relatively low density and relatively high EN of nonmetals is set out in Hein M & Arena S 2013, Foundations of College Chemistry, 14th ed., John Wiley & Sons, pp. 226, G-6.
 * the 23 elements within the scope of the article; and therefore
 * the other varying conceptions of nonmetals and the resulting sets of of nonmetallic elements

Here are extracts from a dozen sources corroborating the low density of nonmetals (#2 also refers to high EN):


 * 1) A nonmetal is an element that usually has a low density
 * 2) Unlike metals, solid non-metals are dull, brittle and not malleable. They also tend to be less dense than metals, and have lower melting and boiling points (apart from carbon). With high electronegativity (see here) non-metal elements ...
 * 3) Nonmetals include gases, liquids , and solids . They are generally dull instead of shiny , and they do not conduct heat or electricity very well . They cannot be shaped into wires or thin sheets , and they tend to have a low density.
 * 4) Nonmetals have a low density.
 * 5) Nonmetals are characterized by lack of luster, lack of conductivity , brittleness , and low density.
 * 6) Nonmetals appear on the right side of the periodic table a . These elements usually have a low density
 * 7) Dull, reflecting light poorly or absorbing strongly Low density
 * 8) Have low density
 * 9) Nonmetals are usually lighter in weight than metals ,
 * 10) Non- metals are generally lighter in weight than metals
 * 11) Non - metals are usually lighter than metals
 * 12) Most nonmetals have no luster, are soft , are poor conductors , and have a low density.

And a dozen referring to high(er) electronegativity:


 * 1) With high electronegativity (see here) non-metal elements ..
 * 2) Table 11.5 shows that the relative electronegativity of the nonmetals is high and that of the metals is low.
 * 3) The Allred Rochow electronegativities of the nonmetals are larger than 1.8, those of the metals are smaller than 1.5
 * 4) Metals, in the lower left corner of the table, have low electronegativities and nonmetals, in the upper right
 * 5) These two trends result in nonmetals generally having higher electronegativities than metals
 * 6) The electronegativities of metals are small while those of nonmetals are large. These data are useful in the classification of metals from non-metals
 * 7) Elements with high electronegativity (such as nonmetals) have a greater ability to attract electrons
 * 8) Metals are the least electronegative elements (they are electropositive) and nonmetals the most electronegative.
 * 9) Some of the elements have high values of electronegativity and some have lower values. Those with low electronegativity values are called metals and those with high electronegativity values are categorized as nonmetals
 * 10) Nonmetals are much more electronegative than metal.
 * 11) The most electronegative elements are the nonmetals on the far right of the periodic table
 * 12) Nonmetals have high electronegativities.

--- Sandbh (talk) 07:04, 24 May 2023 (UTC)

Merge or split?
It seems that it would be much better if either the history section is split and merged with Discovery of the nonmetals, or the opposite, merge the discovery article here. It is short enough to go both ways. ReyHahn (talk) 14:12, 26 July 2023 (UTC)

Halogen pic
How would something like this work for the picture at ? YBG (talk) 02:10, 31 October 2023 (UTC)


 * It looks pretty, and better than I'd expected, and adds interest to the article. Please proceed. --- Sandbh (talk) 03:28, 31 October 2023 (UTC)

Sources pic
I’m experimenting here with a table to replace the one at

Differences from the status quo: YBG (talk) 15:00, 6 November 2023 (UTC)
 * 1) Corrected Te color
 * 2) Add missing period 1, 5
 * 3) Group label 1/17 in place of footnote
 * 4) 2-line legend labels
 * 5) 1-line table header
 * 6) Horizontal “Period” label
 * 7) Parenthetical group/period numbers
 * 8) Legend in L-R order instead of top-bottom, which also places similar sources together
 * 9) Wikitable instead of graphic
 * 10) Somewhat mnemonic/symbolic color selection (I don’t feel strongly about this)
 * 11) Iodine’s two colors are diagonal, not horizontal


 * @Sandb, @Double sharp What do doy think about using this graphic instead of the current one? YBG (talk) 15:40, 6 November 2023 (UTC)
 * I like your proposed version, especially because of #9. Double sharp (talk) 15:42, 6 November 2023 (UTC)

Abundance, sources, uses
@Sandbh, @Double sharp: What do you think of putting each graphic in its proper section? Check out in both desktop and mobile views. YBG (talk) 04:40, 7 November 2023 (UTC)


 * I think that will be OK. --- Sandbh (talk) 22:28, 7 November 2023 (UTC)
 * Implemented YBG (talk) 10:11, 8 November 2023 (UTC)}}
 * I subsequently made some additional changes. Here's a link to the latest:
 * Added clear at the end of each section
 * Removed the table headings expanded section headers
 * Moved the sources legend blocks into the text
 * Some additional changes might be helpful. @User:Sandbh, would you consider looking at these?
 * The uses table refs are identical for each section; it would be nice to have them be more specific
 * The sources table legend is in the text as a table. I'm sure there's a better way to do this, but I don't know what it is.
 * Thanks YBG (talk) 12:09, 8 November 2023 (UTC)
 * Uses table cites have been reorganized to be more specific. For now, I'm happy with the sources table legend. FYI. --- Sandbh (talk) 12:42, 15 November 2023 (UTC)
 * Thanks. BTW, I figured out how to get a hanging indent work with the text, which also serves as the table legend. I want to test it out with a bunch of different screen widths, but once I do I think this whole section is resolved. YBG (talk) 23:00, 16 November 2023 (UTC)
 * And now I've fixed the hanging indent. Everything is resolved in this section. YBG (talk) 05:10, 17 November 2023 (UTC)

It looks good. --- Sandbh (talk) 12:12, 18 November 2023 (UTC)

Whither now (post FAC7)
@Sandbh: Thank you for taking the initiative to resolve the outstanding issues in FAC-7. I wonder if it might be wise to see how many of the reviewers would be willing to become co-nominators? I would be willing to do this under certain circumstances, and I think others might also. Convincing previous reviewers to become co-nominators will improve (but delay) the FAC-8 nomination. For me to be willing to do this, I would need to engage with the FA criteria in a way I have not yet done. For each criterion, I would wish to state the extent to which I reviewed it and list any outstanding issues that need to be addressed before I'm willing to become a co-nominator.

Potential problems with this:
 * Trying to recruit co-nominators this way might not be viewed well.
 * Reviewers might have conflicting criteria that cannot be satisfied simultaneously. If so, far better for this to surface - and hopefully resolve - before FAC-8 than during it!
 * For example, there is an inherent tension between precision and readability. How can we avoid both over-simplification and over-precision? For example, if not done carefully, adding the "tendency-speak" to make statements precise can cause sentences to be clumsy and wordy. If not done carefully, simplifying sentences can over-simplify things or lead to false statements. It will take perseverence and carefulness to resolve this issue.

Is there any interest in pursuing such a process? Is anyone else willing to consider becoming a co-nominator? YBG (talk) 09:34, 23 October 2023 (UTC)


 * I would strongly recommend against renominating so soon unless you have recruited a co-nominator. Otherwise the next FAC might easily degenerate into another wall of text trying the patience of the coordinators. YBG (talk) 00:18, 27 October 2023 (UTC)

The plan is to not renominate until all the discusssion on this page has been concluded. --- Sandbh (talk) 02:11, 31 October 2023 (UTC)


 * @Sandbh That eliminates my concern about a sudden renomination. Thank you.
 * Do I understand you correctly that you would prefer not having a co-nominator? YBG (talk) 21:45, 17 November 2023 (UTC)
 * As I understand it a co-nominator cannot also support or oppose a nomination. --- Sandbh (talk) 11:35, 18 November 2023 (UTC)
 * That makes sense. By definition, a co-nominator supports the nomination. IMO, a co-nomination seems stronger that a mere support, but if you think it is unhelpful or just plain unneeded, I won't press the issue. YBG (talk) 15:08, 18 November 2023 (UTC)

First row anomaly pic
The pic at has a lot of detail not related to the first row anomaly. This makes the picture cluttered and confusing. I've included here an outline of what could be an alternative. YBG (talk) 13:02, 8 November 2023 (UTC)

Please proceed, with the exception that the first rows of the d and f blocks do not need to be shaded. --- Sandbh (talk) 12:45, 15 November 2023 (UTC)


 * @Sandbh I know the d and f blocks don’t have any nonmetals, but they do have 1st row anomalies, don’t they? YBG (talk) 21:50, 16 November 2023 (UTC)

They do. The degree to which the anomalies standout is s >> p > d >f. It doesn't really matter if the d- and f- anomalies are included. Perhaps something like attached image. --- Sandbh (talk) 11:31, 18 November 2023 (UTC)


 * @Sandbh: I like it, especially the inclusion of the atomic numbers. Should I include the group numbers? If so, do they need to be labeled? I'm inclined to consistently include the s/p/d/f block labels but drop the normal shell-filling order s1-2 / p1-6 / d1-10 / f1-14. What do you think? YBG (talk) 15:20, 18 November 2023 (UTC)
 * @Sandbh: OK, I've replace the graphic with a table. Feel free to improve it or revert and discuss how it could be improved. YBG (talk) 06:54, 19 November 2023 (UTC)

Metalloid / PTM comparison
The penultimate paragraph with block quote amounts to saying “The metalloids and PTM are in the middle of the periodic table, one is weakly metallic, the other weakly nonmetallic”. This is not really a fact about the M-oids and PTM, but rather a fact about the general strongly-metallic-to-strongly-nonmetallic PT trend. The text admits that the comparison is only occasionally made. Unlike the group 17 and 18 comparisons, I don't think this paragraph has anything substantial enough here to be included in the 1st paragraph of the section as I added in the now reverted edits. Best to simply delete this paragraph. YBG (talk) 15:39, 30 October 2023 (UTC)


 * @Sandbh, @Double sharp. I’ve seen no word of agreement or disagreement with my suggestion that this paragraph is not needed and should be removed. Thoughts? YBG (talk) 05:06, 3 November 2023 (UTC)
 * I agree with you. Double sharp (talk) 08:21, 3 November 2023 (UTC)
 * Ok, I’ve removed this paragraph. YBG (talk) 13:10, 3 November 2023 (UTC)

Done. --- Sandbh (talk) 12:48, 15 November 2023 (UTC)

Unclassified NM / TM comparison
The penultimate “In terms of PT geography...” paragraph essentially says both classes are between more reactive elements and less reactive elements. This is not really a fact about the UNM and TM, but rather a fact about the general strongly-metallic-to-strongly-nonmetallic PT trend. Unlike the group 17 and 18 comparisons, I don't think this paragraph has anything substantial enough here to be included in the 1st paragraph of the section as I added in the now reverted edits. Best to simply delete this paragraph. YBG (talk) 15:39, 30 October 2023 (UTC)


 * @Sandbh, @Double sharp. I’ve seen no word of agreement or disagreement with my suggestion that this paragraph is not needed and should be removed. Thoughts? YBG (talk) 05:05, 3 November 2023 (UTC)
 * I agree with you. Double sharp (talk) 05:09, 3 November 2023 (UTC)
 * Ok, I’ve removed this paragraph. YBG (talk) 13:10, 3 November 2023 (UTC)

Done. --- Sandbh (talk) 12:48, 15 November 2023 (UTC)

Comparisons in general
If you are willing to delete all four comparison paragraphs, I would entertain the addition at the end of the introduction to Types, a general statement describing NM L-R trend, mentioning that it mostly mirrors the L-R trend in metals. If this seems a good idea, let me know and once all four comparison paragraphs are removed, I'll add it from my offline draft. YBG (talk) 15:39, 30 October 2023 (UTC)


 * I've deleted all four paragraphs, and added one paragraph to the end of the intro to Types section, explaining that a broadly comparable range of types occurs among the metals, from highly reactive to less reactive (even noble). FYI. --- Sandbh (talk) 22:25, 14 November 2023 (UTC)
 * @Sandbh, @Double sharp: I added a new comparison paragraph then removed the old one, and finally reverted those changes leaving no differences. Please comment after looking at the new version to see how it flows; or you could see both with the fuzziness paragraphs between. I will consider any comments before restoring my new version in a day or two. I can already see a couple of places where I could make my proposed text read smoother. YBG (talk) 06:48, 15 November 2023 (UTC)
 * Thanks. I hope to be able to carefully scrutinize this tomorrow morning my time. --- Sandbh (talk) 12:57, 15 November 2023 (UTC)

Sandbh’s analysis of YBG’s alternative

 * Here are the topic sentences of the Types section including YBG's paragraph:


 * The classification of nonmetals can vary, with approaches ranging from as few as two types to as many as six or seven.
 * Traversing the periodic table from right to left, three or four types of nonmetals can be discerned:
 * In the periodic table, metalloids – so metallic they are often not considered nonmetals – come beside post-transition metals, the least metallic of metals.
 * The boundaries between these sets of nonmetals are not sharp.
 * The greatest discrepancy between authors occurs in the metalloid "frontier territory"
 * A broadly comparable range of types occurs among the metals, from highly reactive to less reactive (even noble).


 * Topic sentence 3 breaks the logical flow of ideas. It is not a topic sentence as it does not set out the broad premise of the paragraph. Inserting a paragraph mentioning metals here, rather than at the end of the section, is awkward.


 * YBG, your paragraph in full reads:


 * In the periodic table, metalloids – so metallic they are often not considered nonmetals – come beside post-transition metals, the least metallic of metals. This follows a general left-to-right metallic-to-nonmetallic trend. Surrounding these are more reactive elements (transition metals and unclassified nonmetals); and further outside, the most reactive elements (alkali and alkaline earth metals and halogen nonmetals). The least reactive elements include noble gases on the far right and noble metals buried within transition metals.


 * The statement, "metalloids – so metallic they are often not considered nonmetals" is dubious. Only about 50% of authors actually mention lists of metalloids. It has been know for over a century that metalloids behave chemically mainly like nonmetals.


 * Re, "post-transition metals, the least metallic of metals" that is not so. There are overlaps between the metal types, as is the case with the nonmetal types. Towards the middle of the periodic table are transition metals, such as scandium, iron and nickel, of high to low reactivity. To the right of the transition metals, (from group 13 onwards) are metals such as tin and lead, none of which are particularly reactive.


 * For comparison, here's the last paragraph of the section:


 * A broadly comparable range of types occurs among the metals, from highly reactive to less reactive (even noble). On the left side of the periodic table, and below its main body, are highly to fairly reactive metals, such as sodium, calcium and uranium. Towards the middle of the periodic table are transition metals, such as scandium, iron and nickel, of high to low reactivity. To the right of the transition metals, (from group 13 onwards) are metals such as tin and lead, none of which are particularly reactive.[n 24] A subset of the transition metals (including platinum and gold) are referred to as noble metals on account of their reluctance to engage in chemical activity.[133]


 * Note 24 says:


 * For aluminium, Whitten and Davis[134] write, "[It] is quite reactive, but a thin, transparent film of Al2O3 forms when Al comes into contact with air. This protects it from further oxidation For this reason it is even passive toward nitric acid (HNO3), a strong oxidizing agent. When the oxide coating is sanded off, Al reacts vigorously with HNO3."
 * --- Sandbh (talk) 02:01, 16 November 2023 (UTC)


 * I've further copy edited the last para of this section, and added an image. --- Sandbh (talk) 06:12, 16 November 2023 (UTC)

Discussion of YBG’s alternative
@Sandbh: Your longish post seems to me to have three main objections, which I would like to discuss individually. I would appreciate your effort to keep your responses brief. YBG (talk) 21:41, 17 November 2023 (UTC)

(1) You object to. Would it be acceptable to say "sometimes" instead of "often"? YBG (talk) 21:41, 17 November 2023 (UTC)


 * I suspect it would not be possible to find a supporting citation that refers to metalloids being "so metallic they are often not considered nonmetals." This is especially so given it has been know for ~120 years that metalloids have a predominately nonmetallic chemistry. --- Sandbh (talk) 12:09, 18 November 2023 (UTC)
 * That doesn't answer my question: would it be acceptable to say ? Or perhaps this would be better: ? YBG (talk) 18:23, 18 November 2023 (UTC)
 * I think YBG is right on this one. Anything that would call the chemistry of Te "predominately nonmetallic" would have a hard time not saying the same of some 4d and 5d transition metals (Te forms cationic species at low pH, W doesn't even do that; all W(VI) species involve oxide ligands, but tellurium forms Te(OH)6). As shown at Nonmetal, there's actually quite few properties that distinguish metals from metalloids, other than a slightly weaker tendency to form alloys (and even then, intermetallic semiconductors like Mg2Sn, FeGa3, and Be5Pt exist): the metalloids usually fall within the bounds of metals. (Again, this is mostly thanks to the 4d and 5d metals being complete disasters chemically.) Most people using a "metalloid" category treat them as a third class, neither metal nor nonmetal, as YBG's wording would have it. Double sharp (talk) 09:24, 19 November 2023 (UTC)

(2) You object to, but then you seem to argue as though I had said "least reactive" instead of "least metallic". There are less reactive metals amongst the TM, but are there any that would be considered less metallic (or more nonmetallic) than the PTM? YBG (talk) 21:41, 17 November 2023 (UTC)


 * Ditto; I suspect it would not be possible to find a supporting citation that refers to the PTM as being "the least metallic". OTOH the way the paragraph is constructed now is covered by just one citation. I tried to not use the expression PTM here in order to avoid any controversy as to whether Al is or is not a PTM. If it is regarded as such, then a case could be made that Zn is less metallic than Al. This treads on another controversy as to whether Zn is a transition metal. --- Sandbh (talk) 12:09, 18 November 2023 (UTC)
 * @Sandbh: A couple of questions. (a) Is it true that the PTM is the least metallic class of metals? (b) Is it true that in each period, every PTM is less metallic than any AEM/AM/TM in the same period? I'm definitely not suggesting that we'd use either of these convoluted expressions - I'm just trying to verify my understanding of the situation. YBG (talk) 18:40, 18 November 2023 (UTC)
 * Not, but: (a) not really, the 4d and 5d transition metals are weaker; (b) not really, as in particular thallium is a better metal than tungsten is, and both are in period 6. (Tungsten doesn't even form any ionic halides; in high oxidation states it forms molecular compounds like WF6, and in low oxidation states it forms cluster compounds like W6Cl18. It also doesn't have any aqueous cationic chemistry to speak of, and the most stable oxide WO3 is more acidic than Sb2O3. On the other hand, Tl+ does an okay job of pretending to be an alkali metal cation, and TlF can quite reasonably be described as ionic, although high conductivity of Tl2O3 shows that it's still a weak metal.) Double sharp (talk) 04:59, 19 November 2023 (UTC)
 * @Double sharp: When you say, is “weaker” a synonym for “less metallic” (ie, “more nonmetallic”)? YBG (talk) 23:13, 19 November 2023 (UTC)
 * Yes. Double sharp (talk) 02:20, 20 November 2023 (UTC)
 * (a) Yes. In general terms, the metals to the right of the TM, as a set, are the weakest metals. None of them have any real mechanical strength; most of them are pretty weak chemically. OTOH, some of the early TM are chemically quite strong; there are quite few mechanically strong TM; and several of the TM (noble metals) are chemically weak. To the left of the TM are the successively mechanically weaker and chemically stronger Ln/An and group 1–2 metals. You can get a good appreciation of what’s going on by studying the melting point v. electronegativity chart (for all metals), in the post-transition metal article. (b) Yes, bearing in mind metallic character is a combination of physical and chemical attributes, rather than one or the other. On W and Tl, I suggest the chemistry-based shortcomings present in W compared to Tl, are out-muscled by the mechanical strength of W (e.g. tensile strength ~980 MPa cf ~Tl 10; Mohs hardness 7.5 v. 1.2) and its refractoriness (mp 3,695 K cf. Tl 577).--- Sandbh (talk) 03:49, 20 November 2023 (UTC)
 * Which metals are "weakest" depends on precisely what you're talking about. Chemically, 4d and 5d metals are the weakest. Physically, they are the strongest. Chemically, alkali metals are the strongest. Physically, they are the weakest. For this reason, when talking about metallic strength, it should be clarified what precisely is being compared. Since you were writing about chemical behaviour above, I responded by comparing chemically; if you want to consider both, then any such statement would depend on how you weight the two kinds of properties, and that starts to get into OR. BTW, tellurium (which isn't even a metal) beats thallium on all three physical properties you mentioned (tensile strength 11 MPa vs. 10 MPa, Mohs hardness 2.25 vs 1.2, mp 723 K vs 577), so it's not even that clear that they're good gauges of what good metallicity is. Double sharp (talk) 05:34, 20 November 2023 (UTC)


 * I suggest any concerns about the Mohs hardness of thallium and its lower melting point are out-weighed by the fact that is is a malleable and sectile close-packed metal, with an ionization energy less than 750 kJ/mol, and an EN < 1.9. In contrast, tellurium is a brittle and crumbly open-packed semiconductor with an ionisation energy > 750 kJ/mol, and an EN >= 1.9. That thallium has a metallic chemistry and tellurium has a nonmetallic chemistry is a further consideration. Sandbh (talk) 11:03, 23 November 2023 (UTC)
 * Aren't you kind of proving my point about it not being clear that those properties are good gauges of what good metallicity is? :)
 * Point being, there are a bunch of things that have be considered representative of "metallicity"; since they don't always agree, it's helpful to specify what exactly is meant. Double sharp (talk) 15:34, 23 November 2023 (UTC)

(3) You object to how my paragraph fits into the section flow. I need to think about this more. Let’s wait until after we discuss the other two issues. YBG (talk) 21:41, 17 November 2023 (UTC)


 * First of all, the topic sentence of a paragraph needn’t be the first sentence; in my paragraph, the topic sentence was the second one. Nevertheless I’m happy to follow this style since it has been used throughout the rest of this article.
 * I have recast my paragraph taking into consideration the comments received above.
 * These categories follow the general left-to-right metallic-to-nonmetallic trend in the periodic table. The metalloids – so metallic they are sometimes not considered nonmetals – are just right of the post-transition metals – the least metallic class of metals. Surrounding these are more reactive elements (transition metals and unclassified nonmetals); and further outside, the most reactive elements (alkali and alkaline earth metals and halogen nonmetals). The least reactive elements include noble gases on the far right and noble metals buried within transition metals.
 * @Sandbh, @Double sharp, (and any others), any feedback on this revised paragraph? YBG (talk) 19:45, 20 November 2023 (UTC)
 * The problem with this wording is that the noble metals are a subset of the transition metals, and in fact are almost right next to the PTM (Hg is already quite noble, and Au certainly is).
 * In general, "metallic character increases going left to right" is one of those lies to children that works because it's correct for the elements encountered in the first year of chemistry. It's not really accurate once you consider the d-block elements (actinoids also have some problems with this generalisation, but the d-block has the most exceptions). Nonmetals don't have this problem, but metals do. Double sharp (talk) 09:50, 22 November 2023 (UTC)
 * There is in fact a general trend of increasing electronegativity from Cs to F. Please see Electronegativity: A three-part wave. As DS noted, however, the noble metals are geographically positioned before the post-transition metals. Another issue is that the proposed paragraph mixes the concepts of metallicity with reactivity, which can be confusing. Finally, I’m not sure that supporting citations will be able to be found. The existing form of wording in the article does not suffer from any of these issues. Given this, and speaking frankly, I no longer know why your form of wording YBG, is still being discussed. Sandbh (talk) 10:41, 23 November 2023 (UTC)
 * While the 3- or 4-fold division of nonmetals is well attested, it is my understanding that there is precious little literature support for a comparable division of metals; it isn’t even mentioned at . The multiple pages listed in the ref may all support this 4-fold division or perhaps the division is synthesized from multiple tangential comparisons. Without seeing the original, I hope the former but suspect the latter.
 * I think the noble metals being a subset of the transition metals is the reason why this beautiful and symmetrical scheme has not attracted greater interest.
 * @Sandbh and I both mention reactivity to justify the pairings. I mention metallicity to place these two 4-fold divisions in the broader PT context. Without the metallicity and PT context, there seems to be little justification for including either paragraph, mine or @Sandbh‘s.
 * Although i prefer my approach (seeing the categories as a reflection on metallicity trends) to Sandbh’s, I frankly think the article would be better without either of these paragraphs. @Double sharp, what do you think? Would the article be better without a paragraph comparing the NM categories to M categories? If you want such a paragraph, do you prefer an approach using the M-to-NM trend or one without? YBG (talk) 17:50, 23 November 2023 (UTC)

It’s not clear to me why there is so much ado over a single paragraph that takes up ca. 1% of the article’s size. I’m currently time-challenged and hope to be able to add some further comments later on. Sandbh (talk) 21:59, 23 November 2023 (UTC) A key consideration is that the article opens with a reference to metallic properties and concludes with a comparison of metals and nonmetals. In this context the mid-way broad comparison seems appropriate.

The citation is to Parish's book, The Metallic Elements. He surveys the s-block metals; the f-block metals (a chapter each on Ln and An); the d-block metals (a chapter each on the 3d metals, and the 4d-5d metals (including the noble metals); and the p-block metals.

The relevant paragraph in the nonmetal article is accompanied by a table showing EN ranges for the elements. The pattern of electronegativity is plain to see. For the types of nonmetals, there is a progression from less electronegative to more electronegative. A similar progression occurs among the metals.

Metallicity is broadly related to EN and to reactivity. So, the s- and f-block metals are the most EN/metallic, the ordinary TM are next, then follow the p-block metals, and the noble metals.

Among the metals a similar pattern is seen in the melting point v EN chart in the post-transition metals article. Sandbh (talk) 23:54, 23 November 2023 (UTC)
 * So now metallicity is about EN, but when it comes to comparing W and Tl, it's about physical properties? Double sharp (talk) 03:03, 24 November 2023 (UTC)
 * EN is one aspect of metallicity. While there are a fair number of overlaps among the EN values of the elements, and even overlaps between sets of elements, there is no doubting the overall patterns when comparing sets of elements. The scatter chart of EN x MP values confirms this. Sandbh (talk) 06:17, 25 November 2023 (UTC)
 * Differences between authors on how to categorise elements into sets, differences between EN scales (Allen gives much lower values for noble metals than Pauling does), and differences in EN depending on oxidation state (PbII 1.87 versus PbIV 2.33) rather suggests that there is quite a doubt. Double sharp (talk) 13:35, 27 November 2023 (UTC)

I may as well gently add, once again, it is well known that both metals and nonmetals range from highly to less reactive (even noble). The paragraph under discussion says just that. Sandbh (talk) 01:25, 24 November 2023 (UTC)

Further comments (because at the FAC7 I stopped at Physical properties)

 * Chemical properties


 * I still don't buy the precise wording at the beginning. If you were going to say nonmetals form acidic oxides, then sure. But not acidic compounds in general. There surely are a lot of organic bases. Even in the inorganic realm, probably ammonia is the most famous base with only nonmetallic elements in its formula. Double sharp (talk) 07:35, 30 October 2023 (UTC)
 * Thanks. I intend to change this to say:
 * "Nonmetals possess relatively high values of electronegativity[p. 263] and their oxides are typically acidic.[p. 263] The exceptions concern some amphoteric nonmetallic oxides, such as the dioxides of selenium and tellurium (which nevertheless have a bias to acidity),[p. 446][NB] and water, which is a neutral oxide of hydrogen.[p. 659]
 * The page # cites are to Kneen, Rogers and Simpson 1972, Chemistry: Facts, Patterns & Principles.
 * The NB footnote will say, "Germanium (II) (hydr)oxide has been reported to be more basic than acidic.[G&Z]" The cite is, which is a primary source, hence the "may".
 * I haven't been able to get a clear read on Ge(II) hence the NB footnote.
 * Your thoughts?
 * --- Sandbh (talk) 13:03, 1 November 2023 (UTC)
 * Seems good to me.
 * I think that one should connect the high electronegativity of nonmetals to the acidity of their oxides, as is done here (I think that's based on Wulfsberg's books), since you've just mentioned the former. Also relevant is the oxidation state, which is why I2O is amphoteric whereas I2O5 is acidic. As for explicit examples, I'd avoid getting into the weeds, considering that authors vary about what counts as amphoteric. (Somehow I doubt many people consider N2O5 amphoteric even though it has both acidic and basic properties. :D) I'd just suggest that Sb2O3 be used as the exemplar instead; SeO2 and TeO2 are both stronger acids than As2O3, which is sometimes called just plain acidic already. Also, there's a few nonmetals oxides that display neither acidic nor basic properties.
 * So, perhaps something like this would be good: "Nonmetals possess relatively high values of electronegativity, and therefore their oxides are usually acidic. Exceptions occur when the oxidation state is low, the nonmetal is not very electronegative, or both: thus for example H2O and Sb2O3 are amphoteric. A few nonmetal oxides are neutral, such as CO, NO, and N2O." (I wouldn't count F2O, as it's not really an oxide.) Double sharp (talk) 13:32, 1 November 2023 (UTC)
 * Thanks.
 * I2O apparently reacts with water to give hypoiodous acid.
 * CO and N2O are formally the anhydrides of formic and hyponitrous acid, respectively viz. CO + H2O → H2CO2 (HCOOH, formic acid); N2O + H2O → H2N2O2 (hyponitrous acid). The reference is House JE 2008, Inorganic Chemistry, Elsevier, Amsterdam, p. 441.
 * In water, NO reacts with oxygen to form nitrous acid HNO2.
 * Per your words, I'll change the sentence to:
 * "Nonmetals possess relatively high values of electronegativity, and their oxides are therefore usually acidic. Exceptions occur when the oxidation state is low, the nonmetal is not very electronegative, or both: thus, for example, water H2O and antimony trioxide Sb2O3 are amphoteric.
 * Wulsberg does not mention EN in the context of oxides but does mention low oxidation states.
 * Gervasini (2013) mentions both aspects so I'll cite them. They don't give specific examples of amphoteric oxides so this'll require another cite.
 * Gervasini A 2013, "Characterization of acid–base sites in oxides", in Auroux A (ed.), Calorimetry and Thermal Methods in Catalysis, Springer Science, Heidelberg, pp. 319–352,
 * --- Sandbh (talk) 01:41, 2 November 2023 (UTC)
 * Yup, this is fine now.
 * Hypoiodous acid has a high pKa (~11), comparable to clearly amphoteric Sb(OH)3 (11.0 per G&E p. 51) and Al(OH)3 (11.2). Thus it can quite easily end up protonated in aqueous solution.
 * Regarding the neutral oxides, CO and N2O are only formally anhydrides: in practice the reactions with water hardly occur. Greenwood and Earnshaw outright say that N2O cannot be considered the anhydride of hyponitrous acid (p. 444, 2nd ed.): [N2O] is not to be regarded as the anhydride of hyponitrous acid since H2N2O2 is not formed when N2O is dissolved in H2O (a similar relation exists between CO and formic acid). As for NO, the reaction does not occur in the absence of oxygen, though I'll grant that in normal conditions it is there. :) Double sharp (talk) 03:39, 2 November 2023 (UTC)
 * Curiously, House 2013, Inorganic Chemistry, 2nd ed., p. 427 says that:


 * Because CO is a slightly acidic oxide, it reacts with bases to produce formates.


 * CO + OH− → HCOO−


 * It seems then that the only peculiar oxides are water, being amphoteric, and N2O being neutral. --- Sandbh (talk) 00:55, 10 November 2023 (UTC)
 * Done. (hopefully) --- Sandbh (talk) 03:24, 2 November 2023 (UTC)
 * @Double sharp Does this resolve the concerns raised in this bullet? YBG (talk) 06:17, 15 December 2023 (UTC)
 * Yes. Double sharp (talk) 06:43, 15 December 2023 (UTC)


 * Tangentially, why are we looking only at solid nonmetals? Firstly, you're citing each one to its own source, which makes me wonder if it is a SYNTH to look only at them. Secondly, if it were really a characteristic property of nonmetals, then you'd expect that the strongest reactive nonmetals would be even more clear-cut examples. But fluorine reacts with concentrated nitric acid to produce FNO3! I think it would be better just to talk about oxoacids and the acidic hydrides. Double sharp (talk) 07:35, 30 October 2023 (UTC)
 * Thanks. I was looking at the solid metals given the elemental gases are nonmetals and of the two liquid elements, Br is an insulator (i.e. a nonmetal).
 * Citing each one to its own source strikes me as compiling a list rather than synthesising new knowledge, per se. How do you see that?
 * FNO3 apparently decomposes in water to form O2, OF2, HCl, and HNO3. I guess that makes it an acidic compound.
 * --- Sandbh (talk) 00:00, 2 November 2023 (UTC)
 * The removal is fine with me. The way I see it, if you have a specific source saying the general statement, it's OK to cite illustrative examples to different sources; but if you don't have a specific source saying the general statement, it starts being SYNTH.
 * I think that people usually mean Brønsted acids when "acid" is used without qualification, but this is moot now. Double sharp (talk) 04:07, 2 November 2023 (UTC)
 * I agree with @Double sharp about SYNTH. YBG (talk) 04:33, 3 November 2023 (UTC)
 * Done. (hopefully) --- Sandbh (talk) 03:24, 2 November 2023 (UTC)
 * @Double sharp Does this resolve the concerns raised in this bullet? YBG (talk) 06:17, 15 December 2023 (UTC)
 * Yes. Double sharp (talk) 06:43, 15 December 2023 (UTC)


 * 18-electron vs duet/octet is not about metals vs nonmetals, but about transition vs main-group. Obviously, the alkali metals are trying to get a nice, stable full shell; it's just that it's much easier for them to do it by shedding the outermost one. Double sharp (talk) 07:35, 30 October 2023 (UTC)
 * Done. --- Sandbh (talk) 06:47, 8 November 2023 (UTC)
 * @Double sharp Does this resolve the concerns raised in this bullet? YBG (talk) 06:18, 15 December 2023 (UTC)
 * Yes. Double sharp (talk) 06:43, 15 December 2023 (UTC)


 * It should probably be noted that these generalisations are at their best for the strongest nonmetals. Near the borderline, especially for the metalloids, it is quite different. I think this article gets at it quite well (section 5), though I wouldn't suggest using its idiosyncratic terminology. The point is that the very strongest nonmetals are really "the opposites of metals" in all ways (i.e. extremely high EN, forming ionic bonds with the metals, being quite happy in negative oxidation states, forming strong acids, and going for simple or hydrated anions in preference to oxyanions), whereas the other ones tend to compromise more. Double sharp (talk) 07:35, 30 October 2023 (UTC)
 * Done. (hopefully). The third paragraph of the Chemical properties subsection now reads:
 * Furthermore, nonmetals typically exhibit higher ionization energies, electron affinities, and standard reduction potentials than metals. Generally, the higher these values are (including electronegativity) the more nonmetallic the element tends to be.[71] For example, the chemically very active nonmetals fluorine, chlorine, bromine, and iodine have an average electronegativity of 3.19—a figure[n 10] higher than that of any individual metal. On the other hand, the 2.05 average[n 11] of the chemically weak metalloid nonmetals falls within the 0.70 to 2.54 range of metals.[72]
 * --- Sandbh (talk) 12:11, 9 November 2023 (UTC)
 * @Double sharp Does this resolve the concerns raised in this bullet? YBG (talk) 06:18, 15 December 2023 (UTC)
 * Yes. Double sharp (talk) 06:43, 15 December 2023 (UTC)

Double sharp (talk) 07:35, 30 October 2023 (UTC)
 * Are high oxidation states in groups 15 and 16 really unusual? I kind of doubt it considering that this is the majority behaviour. Nitric and sulfuric acids are familiar even in the school chemistry lab. I'd rather name the last section "higher oxidation states" than "unusual oxidation states" for this reason.


 * Done. --- Sandbh (talk) 12:29, 9 November 2023 (UTC)
 * I still think the "higher oxidation states" section has problems: nitrogen already has oxidation state +5 in nitric acid, which is a familiar compound. Moreover, the actual oxidation states in H2S and HF for the non-hydrogen elements are −2 and −1, not 2 and 1; and the oxidation state of Xe in XeF2 is +2 (for an actual example of +8, you'd need XeO4). Even coordination number isn't an accurate phrasing because of species like NH4+, H3O+, and H2F+. Double sharp (talk) 13:50, 15 November 2023 (UTC)


 * Thanks. I've rewritten this paragraph to address your well-raised oncerns.


 * PS: I've added a paragraph to this section re multiple bond formation. --- Sandbh (talk) 01:11, 16 November 2023 (UTC)
 * @Double sharp Does this resolve the concerns raised in this bullet? YBG (talk) 06:22, 15 December 2023 (UTC)
 * Yes. Double sharp (talk) 06:43, 15 December 2023 (UTC)

--- Sandbh (talk) 01:11, 16 November 2023 (UTC)


 * I’ve taken the liberty of adding multiple signatures to facilitate replying to each point independently using the neat new reply feature. @Double sharp, if you object, feel free to revert. YBG (talk) 06:22, 31 October 2023 (UTC)
 * No problem. :) Double sharp (talk) 07:01, 31 October 2023 (UTC)