Talk:Periodic table/Archive 11

recolour group 12 as post-transition metals?
Sandbh has written at WT:ELEM:

My impression has been that (a) authors who show 3–11 give sound reasons for excluding group 12, whereas (b) authors who show 3–12 either say nothing and hope nobody raises a hand at the back of the class, or they offer weaker or superficial reasons for including group 12.

Cotton et al., recently a US standard, are an example of (a). They define transition elements as those having partly filled d shells, which covers groups 3–10, plus those that have partly filled d shells in any of their commonly occurring oxidation states, thereby including group 11 (Cu, Ag, Au). The group 3 elements are counted as transition metals, but since the properties of these metals are "quite different" from those of the regular d-block elements, they are treated, on chemical similarity grounds, in the chapter on the lanthanides. The group 12 elements (Zn, Cd, Hg) are treated as main group metals, since none of these elements give rise to compounds in which d electrons are lost.

Greenwood and Earnshaw are an example of (b). They write that the d-block elements (groups 3–12) are commonly described as "transition elements". On the group 3 elements they note that, "although each member of this group is the first member of a transition series, its chemistry is largely atypical of the transition elements." On the group 12 elements they comment that, "in view of the stability of the filled d shell, these elements show few of the characteristic properties of transition metals despite their position in the d block of the periodic table." They add that zinc resembles transition metals in forming complexes; cadmium is "rather similar" to zinc; and that many compounds of mercury (and cadmium to a lesser extent) are highly coloured, which is a characteristic of transition metals.

Since the literature is roughly divided on this point, and we need to go one way or t'other in colouring our table, it appears preferable to occupy the arguably stronger ground of 3–11 rather than the dubious ground of 3–12.

I don't mind treating Sc-Y as (incipient) transition metals. The addition of the d-electron confers transition metal physical properties, as noted by Greenwood and Earnshaw, and that's good enough for me in terms of periodicity. OK they don't display hardly any of the characteristic chemical properties of transition metals. I can live with that since it provides an illustrative contrast with the group 4–11 transition metals and shows the chemical influence of d electrons (in addition to the impact on physical properties.

Towards the other end of the d block, are the group 11 twilight zone transition metals and their capacity to demonstrate both transition metal chemistry and main group chemistry. Effectively, they can also be regarded as incipient main group metals.

Of course, by the time we get to group 12 there is no d-block chemistry, and there is no d electron cohesion contribution to physical properties, as demonstrated by the abrupt and significant reduction in melting and boiling points in passing from group 11 to group 12.

The reported synthesis of HgF4 carries near enough to zero weight, given (if it really does exist) it would represent something on the order of one-millionth of the chemistry of mercury, and even then at only a few degrees above absolute zero.

In our transition metal article I'd be inclined to still discuss the group 12 elements, at least for comparative purposes (presuming they were colour categorised as PTMs).

In conclusion I'd support group 12 as post transition metals on the grounds of superior chemical and physical arguments.

The fact that IUPAC's Gold Book definition follows Cotton is another point in favour of this classification. Yes, we have been known to disregard IUPAC when common usage suggests otherwise, but this issue tends to be split 50–50 between textbook authors. What pushes me finally over the line to removing group 12 from the transition metals is that people who include them in the transition metals proper generally have to point to lame arguments to keep them in. Group 12 just does not show either the chemical or physical properties of transition metals, whereas groups 4–10 show both, group 3 (including the lanthanides and actinides) shows the physical properties, and group 11 shows the chemical properties.

We can of course cover the differing conceptions of what a transition metal is in Wikipedia when the issue is relevant. However, it seems to me that the best way to go as a default is to give the classification that is most representative of an element's chemistry (that's why we don't colour lanthanum as a transition metal, for example). Thus I think it is better to colour Zn, Cd, Hg, and Cn as post-transition metals.

Comments? Double sharp (talk) 08:28, 30 October 2016 (UTC)


 * If you wish to comment, please go to -- YBG (talk) 04:24, 30 November 2016 (UTC)

Image updating for new named elements
The image under the section "First systemization attempts" is not up to date, still using placeholder names. If someone could put a updated image there it would be greatly appreciated. — Preceding unsigned comment added by Fig28awsome444 (talk • contribs) 02:36, 2 December 2016 (UTC)

Element notation
Is there a reason why 12 letters of the ABC are not used in the Periodic table? A,D,E,G,J,L,M,Q,R,T,X,Z


 * examples
 * Aluminium - A
 * Dysprosium - D
 * Europium - E
 * Galium - G
 * Lithium - L
 * Magnesium - M
 * Ruthenium - R
 * Titanium - T
 * Xenon - X (The onley element begining with X)
 * Zinc - Z

יהודה שמחה ולדמן (talk) 00:59, 25 December 2016 (UTC)


 * A used to be argon, but it was changed to Ar (presumably because, since it would usually occur alone, it would look fantastically confusing). D is deuterium and T is tritium. J was once used for iodine, from German Jod (today Iod is used, though you may find this usage from as recently as the 1970s). G used to be for beryllium, which previously was called "glucinium" (for the sweet taste of its salts, which are however fantastically poisonous; the name "beryllium" was suggested instead because some yttrium salts are also sweet). Some of the others are "generic" symbols: E is for any electrophile, L for any ligand, M for any metal, R for any alkyl group (sometimes also for radicals), and X for any halogen (sometimes X, Y, and Z are used when multiple generic elements from the same group are needed, even though Y is also yttrium). That leaves Q, which is easy to explain because no element has it in its name. Double sharp (talk) 04:56, 25 December 2016 (UTC)


 * Strictly speaking, generic symbols are not an obstacle for an element symbol. I personally think that in most cases, two-letter symbols are better because they immeditely provide more context. I remember that when Berkeley first synthesized einsteinium, they wanted to use the symbol E. The current symbol Es is better as it does not make you think for another half a second, "what 'E' are we talking about?", since einstenium is a rare (in fact, sythethic) element.
 * Hydrogen, oxygen, and other one-letter elements are very common. They don't need that context.
 * (Also, just since you mentioned Jod: it is still the norm, at least per actual usage, in German outside chemistry per my knowledge. (After writing this, I checked German Wiki. The article begins with "Iod (standardsprachlich: Jod)," so I must be right.) I can easily tell the same is correct for Russian, which I only learned from Wiki, as I had never encountered the spelling "иод" (iod) in real life. Chemists are keen on regulating spellings, apparently: see WP:ALUM to get an example from English.)--R8R (talk) 10:21, 25 December 2016 (UTC)
 * To some extent I think yttrium should have remained as Yt, because we want Y fairly often as the natural follow-up to generic X. You are right that they are not obstacles (we deal with it for yttrium), but these meanings are essentially so standardised that it would be needlessly confusing, so even if they are not forbidden de jure (as far as IUPAC can be considered such) they essentially are de facto.
 * Also, thanks for the interesting information about iodine! Most of the German literature I read about it is naturally chemical-oriented and hence uses the spelling with the i. The spelling regulation is useful for sorting and indexing databases, at least: no one wants to search for iodine oxides under both "I" and "J". Double sharp (talk) 10:44, 25 December 2016 (UTC)

Categories
I suggest organization of elements into these categories:
 * Alkali metals: Li, Na, K, Rb, Cs, Fr
 * Alkaline earth metals: Be, Mg, Ca, Sr, Ba, Ra
 * Lanthanides: La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb
 * Actinides: Ac, Th, Pa, U, Np, Pu, Am, Cm, Bk, Cf, Es, Fm, Md, No
 * Transition metals:
 * Platinum group: Fe, Co, Ni, Ru, Rh, Pd, Os, Ir, Pt
 * Noble metals: Ru, Rh, Pd, Ag, Os, Ir, Pt, Au
 * Coinage metals: Cu, Ag, Au
 * Volatile metals: Zn, Cd, Hg
 * Superheavy elements: Lr, Rf, Db, Sg, Bh, Hs, Mt, Ds, Rg, Cn
 * Other transition metals: Sc, Ti, V, Cr, Mn, Y, Zr, Nb, Mo, Tc, Lu, Hf, Ta, W, Re
 * Post-transition metals:
 * Icosagens: Al, Ga, In, Tl, Nh
 * Crystallogens: Sn, Pb, Fl
 * Pnictogens: Bi, Mc
 * Chalcogens: Lv
 * Superheavy elements: Nh, Fl, Mc, Lv
 * Metalloids:
 * Icosagens: B
 * Crystallogens: Si, Ge
 * Pnictogens: As, Sb
 * Chalcogens: Te, Po
 * Halogens: At
 * Nonmetals:
 * Polyatomic nonmetals:
 * Crystallogens: C
 * Pnictogens: P
 * Chalcogens: S, Se
 * Diatomic nonmetals:
 * Hydrogen: H
 * Pnictogens: N
 * Chalcogens: O
 * Halogens: F, Cl, Br, I
 * Superheavy elements: Ts
 * Noble gases: He, Ne, Ar, Kr, Xe, Rn, Og
 * Superheavy elements: Og

What do you think about this system? 108.66.232.14 (talk) 01:20, 14 February 2017 (UTC)


 * This article is about The periodic table of the elements. If you would like to organize elements into new categories, feel free to write up a proposed organizational scheme for the periodic table, submit it for peer review and publication in a journal with a reasonably high impact score. Once your scheme has been published and accepted by the academic community, bring it back here for inclusion in the article. - Sum mer PhD v2.0 02:26, 14 February 2017 (UTC)


 * This is not a proposal to re-categorize elements; it is instead a proposal to categorize the elements into subcategories (such as Superheavy elements). 108.66.232.14 (talk) 02:43, 14 February 2017 (UTC)


 * If you have reliable sources showing that these subcategories are widely used re the periodic table, please provide those sources.


 * If the subcategories are not widely used in re the periodic table, there is nothing to discuss here. - Sum mer PhD v2.0 02:50, 14 February 2017 (UTC)


 * See Group (periodic table) and Superheavy element. 108.66.232.14 (talk) 03:01, 14 February 2017 (UTC)

This system is OK. Nearly all of the categories are shown on the periodic table in the article, here. The refractory metals and the noble metals are mentioned just below that table, here. Other category names are listed in Names for sets of chemical elements. Sandbh (talk) 06:27, 14 February 2017 (UTC)
 * One flaw in your proposal is that you mix up two categorisation schemes. From "Alkali metals, ..." (by metallic characteristics) you flip into "Superheavy elements", (by atomic mass). That is the same as sorting a heap of vegetables by color in the morning and the rest, in afternoon, by size. -DePiep (talk) 13:03, 14 February 2017 (UTC)

You might like to ask WikiProject_Elements about adding extra category names to the info box for each element. For example, gold's Element category ony shows as transition metal, but it is also a coinage metal, a native metal, a noble metal, a platinum group metal, and a precious metal. Sandbh (talk) 23:02, 14 February 2017 (UTC)
 * I'd support that. Could also have transactinide and superheavy metal. -DePiep (talk) 06:06, 15 February 2017 (UTC)

Another format
This is a fascinating format that I had not seen before and a wonderful way of expressing the positions of Yttrium and Scandium and many other things that otherwise seem to be exceptions to the concept of the table.

Does anyone know where it comes from? Andrewa (talk) 07:24, 2 April 2017 (UTC)
 * I might suggest that it came from original research. ^_^
 * Actually I have thought about something like this, but I would think that I would rather show this by duplicating both the group II and the group III elements, as well as hydrogen. Then I'd have H above both Li and F, Be and Mg above Ca and Zn, B and Al above Sc and Ga, and Sc and Y above La and Lu. But we would still be incomplete: Eu and Yb would seem to want to be in group II as well, with La, Gd, and Lu (and Ac, Cm, and Lr) all in group III, and a note on the A and B groups would also be nice (putting B–F and Al–Cl above Sc–Mn), along with a link of Th–Pu to groups 4–8. A frightful mess! Geoff Rayner-Canham's Inorganic Chemist's Periodic Table is not OR and attempts to do something similar (though I would personally have put La and Ac in group 3, with Lu and Lr also duplicated below them in little rectangles as well as putting them at the end of the Ln and An series). Double sharp (talk) 07:30, 2 April 2017 (UTC)
 * The French, Spanish, Italian and Esperanto Wikipedias all use this diagram, but the French says nothing about it other than what is in the English Commons description. That's the only one of those languages in which I have any competence, but the others seem much the same. Tried Google image search but got only Commons and mirrors of either French or English Wikipedia (and none of the English hits actually use the diagram).
 * Geoff Rayner-Canham's table is probably very useful to a serious student of chemistry (I was one once) but my reaction is it's not at all suitable for a general encyclopedia... far too cluttered. Andrewa (talk) 08:11, 2 April 2017 (UTC)
 * Yes, I agree. It is worth listing under a list of alternatives, but I think it's too confusing for general use. Double sharp (talk) 09:38, 2 April 2017 (UTC)
 * What is confusing about it? It seems to reflect the various controversies (confusions?) rather well. That's not confusion, that's clarification IMO. Andrewa (talk) 13:02, 2 April 2017 (UTC)
 * It does, but my concern is that to appreciate it fully you kind of already need to know the chemistry in question. If you've just started middle-school chemistry and all you know are the shells and perhaps a glimmer of understanding of the spdf blocks, putting aluminium over scandium looks like nonsense. Only when you know the chemistries of Al3+ and Sc3+ does it start to make sense, but then you seem to need to know the similarity to understand that there is a similarity. Without knowing it, it just looks confusing to move Al over. Maybe I'm just overthinking it, though. Double sharp (talk) 13:44, 2 April 2017 (UTC)

The table in the top right corner is rather interesting.

The biggest objection would be that it breaches the basic principle of one place, one element. See: Scerri, E. (2012). "Mendeleev's Periodic Table Is Finally Completed and What To Do about Group 3?" Chemistry International. 34 (4).

That aside, we can have some fun with this one.

Stretching H across groups 1 to 17 reminds me of the various attempts to place it above group 1 or 14 or 17. It is a reasonable interpretation of the fact that the first period has only one reactive element in the form of H, so it has to do the work of representing all of the comparatively reactive non-noble gas elements.

Stretching boron is viable. On the analogy between boron and metals, Greenwood, of G&E fame commented that: "The extent to which metallic elements mimic boron (in having fewer electrons than orbitals available for bonding) has been a fruitful cohering concept in the development of metalloborane chemistry ... Indeed, metals have been referred to as "honorary boron atoms" or even as "flexiboron atoms". The converse of this relationship is clearly also valid ..." Greenwood NN 2001, 'Main Group Element Chemistry at the Millennium', Journal of the Chemical Society, Dalton Transactions, vol. 14, pp. 2055–66, doi:10.1039/b103917m

Aluminium is cute given it can form anionic aluminates, such behaviour also being seen in the transition metals, with things like scandates, ferrates, and zincates. Oh, and let's not forget the resemblance to Sc.

Stretching Sc and Y in that way so that they span the Ln is good too. Mind you, Bill Jensen wrote along these lines: "The two boxes below Sc and Y…contain either the atomic numbers 57–71 and 89–103 or the symbols La–Lu and Ac–Lr, respectively, thus indicating that all 30 of the elements in the footnote belong in just those two boxes. Expanding such a table into a 32 column table would require one to stretch the boxes for Sc and Y so that they span all 15 of the inserted columns." He then described this approach as "antiquated" and an interpretation that a modern inorganic chemist would not advocate, unless "they have lost all contact between the underlying premises of their periodic table and the facts of chemistry". Jensen, WB (2008). "The Periodic Table: Facts or Committees?". Journal of Chemical Education. 85 (11): 1491–1492. doi:10.1021/ed085p1491.2.

I was going to bag this layout on the grounds of Scerri's principle and Jensen's criticism, but I have to say it made me think. Sandbh (talk) 10:36, 2 April 2017 (UTC)


 * The biggest objection would be that it breaches the basic principle of one place, one element. Exactly. It's a bit of lateral thinking by someone, and rather good lateral thinking IMO. Perhaps Jensen just could not make this step?
 * Fascinating article by Scerri, but is what it says really incompatible with this version? It seems to support it to me.
 * I'm not saying use this to replace the more conventional version(s), not by any means. But to me it's a good way of explaining at least some of the reasons that there are several of them, and why IUPAC does not endorse any particular one of these.
 * But I can't add it to the article myself for two reasons. Firstly, I'm sure others here are more qualified to do so. Second but perhaps more important, English Wikipedia has higher standards of verifiability than some others, and it seems higher than the four that already use this image. We need a source for it IMO.
 * And I don't have one. I was hoping someone else lurking on this page might. Evidently not, but it might be worth keeping an eye out for it. Andrewa (talk) 13:02, 2 April 2017 (UTC)

,, thanks for your time on this.

We all three seem to have found some new insights in this slightly radical format. As pointed out above, unlike the various geometries in both two and three dimensions, this one takes a step away from one of Mendeleev's original assumptions. Is it not then reasonable to assume that others would find it helpful too?

But I cannot stress highly enough I do not suggest using it to replace the more traditional format. Andrewa (talk) 22:51, 2 April 2017 (UTC)
 * Perhaps(?) the easiest way to be able to accommodate this in the periodic table article is to (a) get it published on the internet database of perioic tables, with some accompanying notes; and then (b) mention it in a note in our article, graphic included. It's worth trying. Another probably harder way would to write the words noting the relationships involved, probably no worries about citations here, and then turn the words into a picture. Could be tricky, but. Sandbh (talk) 01:34, 3 April 2017 (UTC)
 * This is a drawing excercise, not a scientific statement. Are we supposed to find them ourselves, as the following contributions show? -DePiep (talk) 07:34, 3 April 2017 (UTC)
 * Well, there you go. I was at a library today looking for one thing and saw another: "[The] transition metals…have…[Allred-Rochow] electronegativities ranging from 1.2 to 1.75, but generally they cluster around 1.5, which is just about the EN of aluminium (1.47). So the physical properties of the elements themselves and the chemical properties of their compounds (at least those with the transition metal near a formal oxidation state of 3+, like aluminium in its compounds) should resemble those of aluminium. This is generally true, although there are substantial variations within this large group of elements." Porterfield WW 1972, Concepts of chemistry, W · W · Norton & Company, New York, p. 828 Sandbh (talk) 06:50, 3 April 2017‎ (UTC)
 * ...hence Rayner-Canham moving Al over to above Sc as the "patriarch" of the transition metals, just like how Sc and Y over La become the "patriarchs" at the top of the wide family tree of the rare earths. This does the same thing, but more spectacularly! Boron also seems reasonable to stretch, but (forgive the pun) the resemblance of hydrogen here seems to be a bit "stretched", unless we take the rather philosophical position that it is in its singularity representative of all the reactive elements and none of them simultaneously. Double sharp (talk) 06:57, 3 April 2017 (UTC)
 * I forgot about Rayner-Canham; that's a good one. I'm sure I've seen references to H as stretchy element, somewhere, It's kind of the same as putting H at the centre of the spiral periodic-tables, in no group, isn't it? Sandbh (talk) 07:19, 3 April 2017 (UTC)
 * My impression of H was always that it didn't really have visible family connections with anything else, but if you squinted you could see some "alkali-metalness" in there. ^_^ I honestly prefer "floating" H then stretching it like this – it feels more related to none of the elements than to all of them, if that very philosophical phrasing even makes sense. (And considering how often H is "floated" above the table, for all that it breaks the idea that the periodic law is supposed to be valid for every element from hydrogen to oganesson, I seem to be in good company there.) Double sharp (talk) 07:23, 3 April 2017 (UTC)


 * It is not an 'alternative', it is a sloppified periodic table. Completely unclear which scientific statement is being made. Someone ate the topping of this pizza. A bum is not a hotdog. First add group numbers, then come back with a new question. -07:28, 3 April 2017 (UTC)

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Update images
Files Periodic table 14CeTh form---Group 3 = Sc-Y-La-Ac.jpg, Periodic table 14LaAc form---Group 3 = Sc-Y-Lu-Lr.jpg, Periodic table 15LaAc form---Group 3 = indeterminate.jpg and 32-column periodic table-a.png should be updated for Fl coloring, plus Discovery of chemical elements.svg and ShortPT20b.png for newly discovered elements.

--5.43.78.13 (talk) 18:34, 28 June 2017 (UTC)

Alignment and centering
I propose using for three template tables for group 3 variants, and for other three or so non-template tables so that they are centered and have proper padding on mobile view.
 * and
 * etc.
 * etc.
 * etc.
 * etc.

Caption should be broken using  because   will ensure box right border is next to the right part of the system (thus centering it) but caption can expand box to the right and should be no wider than system.

--5.43.78.13 (talk) 18:34, 28 June 2017 (UTC)

RfC: Colour group 12 as post-transition metals
I am seeking comments on a proposal to color code the group 12 elements as post-transition metals in the Wikipedia periodic table, rather than transition metals as they are currently color coded.

The RfC can be found here. Sandbh (talk) 23:07, 9 August 2017 (UTC)

RfC: Replace categories of poly/diatomic nonmetal with less active/active nonmetal
I am seeking comments on a proposal to change the name and composition of two of the colour categories appearing on our periodic table, as follows:

The RfC can be found here. Sandbh (talk) 23:55, 9 September 2017 (UTC)

change to periodic table
should flerovium and copernicium be shown as gases — Preceding unsigned comment added by Stburdgewiki (talk • contribs) 10:58, 18 November 2017 (UTC)
 * They probably are, but we have not actually done the experiment on more than one atom at a time, which is why they are not yet shown as such. Single atoms of anything are gaseous. Double sharp (talk) 13:05, 18 November 2017 (UTC)

Neutronium
Having just read up on neutronium (the real thing, not the version prevalent in science fiction), I was surprised to learn that a large minority of periodic tables list neutronium as element number 0. Would there be any interest in doing the same here? Jtrevor99 (talk) 19:20, 29 November 2017 (UTC)
 * Apparently not. Ah well, perhaps it's for the best. It could be confusing. Jtrevor99 (talk) 18:07, 11 December 2017 (UTC)
 * It might well be common among "periodic table fans", but I would be very surprised to see a serious source doing that. Double sharp (talk) 05:54, 12 December 2017 (UTC)

Semi-protected edit request on 5 January 2018
Change 94 natural elements to 92 natural elements 97.95.160.180 (talk) 02:44, 5 January 2018 (UTC)
 * ❌ because there are 94 natural elements; trace quantities of Np and Pu are continually generated by neutron activation of natural U. Double sharp (talk) 02:47, 5 January 2018 (UTC)

TFA rerun
Any objections to throwing this article into the current pile of potential TFA reruns for next year (currently being developed at User:Dank/Sandbox/2)? Any cleanup needed? - Dank (push to talk) 13:55, 10 September 2017 (UTC)
 * Above an RfC is announced, I'd prefer waiting for its result implemented (quite a big thing in PT world). Also, in the longer run we'd like/need to improve the background colors of the graphic PT. 2018? OTOH, has 26 articles, maybe others can be TFA'ed earlier. btw, see also Wikipedia talk:WikiProject Elements (WT:ELEM). -DePiep (talk) 16:55, 10 September 2017 (UTC)
 * Sure, DePiep, I'll remove it from the list I'm working on this week. - Dank (push to talk) 17:20, 10 September 2017 (UTC)


 * It's been rescheduled then, see Today's featured article/January 8, 2018. A pity the RfC (on re-categorising the non-noble nonmetals) did not mature in a color change yet. Should we ask for 6 more months? -DePiep (talk) 10:29, 11 December 2017 (UTC)
 * Personally, I prefer the 32-column form for the blurb. Would be a huge improvement. -DePiep (talk) 10:29, 11 December 2017 (UTC)
 * The 32-column form is rarely seen in text-books so it was appropriate to stick with the 18-column form. Sandbh (talk) 22:59, 22 January 2018 (UTC)
 * It's an editorial choice only, not by scientific source. Also, we know how imprecise many of those textbooks are wrt this. -DePiep (talk) 09:34, 23 January 2018 (UTC)

Ah, this is quite a bit too late, but I was totally expecting the periodic table TFA re-run to be on its 150th anniversary next year. Oh, well. --Paul_012 (talk) 08:59, 22 January 2018 (UTC)

Period number in the PT: show encircled like &#x2460;
We could show the period numbers in a PT always encircled: &#x2460;, &#x2461; , &#x2466; instead of plain numbers, equally linking to the period page. See current Periodic table/sandbox. They are formal Unicode characters like etc. The links have no underlines. Font-size may need tweaking.

Consideration: the periodic table is crowded with numbers (digits). Adding the dedicated circle would give the period number a visual distinction, easily recognisable and nicely associating with "periods"="circular". All our periodic tables could apply it. - DePiep (talk) 14:05, 6 March 2018 (UTC)
 * I do not think this is a good idea, because the difference in font (compare 1 vs ①) is distracting and it is not standard practice. Double sharp (talk) 12:19, 13 March 2018 (UTC)
 * The difference is size only, and that can be adjusted. Also, when all period numbers are like this, there is nothing tot "differ" with. "it is not standard" &mdash; there is no "standard" in this re PT graphics, as we have discovered. Most important point: by adding this graphic effect, the number stands out as something immediately recognisable. It even reduces the need to keep clarifying "this is the period number". Already in mobile view, when zoomed in to ~single cell level, it makes its meaning clear. - DePiep (talk) 12:25, 13 March 2018 (UTC)
 * Yes, there is a difference in apparent font: the circled numbers are not in the same style as the non-circled numbers even if they are part of the same font. Additionally, stylisation of numbers was already common for groups (whence the Roman numerals for them), and putting a stylisation for the periods suggests that that is something that is commonly done: it just isn't. In fact, the period numbers are sometimes just left out entirely; they are chemically much less homogeneous than the groups and if anything should not be given much of an emphasis. Double sharp (talk) 03:54, 14 March 2018 (UTC)

Atomic Masses
I came here to check the value of an atomic mass. Wikipedia will surely have a nice table, I thought. To my surprise, it has many but **none** provide values of atomic masses!? Is that a new trend? If so, I missed it. Who/what institution promoted it? If not, what is the rationale behind? This seems like reinventing the wheel. I would find it ok to show a simplified, to the point of being ridiculous, periodic table, if a traditional one, which include as well masses would also be shown. What is the rationale of hiding that information and forcing the user to go on following further links to check these values?? — Preceding unsigned comment added by 99.245.64.82 (talk) 21:33, 9 October 2017 (UTC)
 * Which atomic mass did you look for? Why did you expect to find such a property, of 118 elements, in an article named "Periodic table"? -DePiep (talk) 23:19, 9 October 2017 (UTC)
 * Nevertheless, atomic mass is the number one reason why chemists look up the periodic table, and you will find it on pretty much all the ones they actually use, so I understand and agree with this request. After all, Z is also a property of 118 elements, and in compounds you can have quite a few elements to look up the atomic masses of. Double sharp (talk) 02:39, 20 November 2017 (UTC)
 * I have edited the hatnote under "Overview" to say "For a more detailed periodic table including atomic weights, see Periodic table (large cells)." This illustrates why the atomic weights aren't in the periodic table figure here – then it wouldn't fit on the screen. Nevertheless, I would be in favour of including figures rounded to three or four significant figures for this article. Double sharp (talk) 03:42, 6 March 2018 (UTC)
 * See Periodic table/sandbox. Issues:
 * It's a mockup, I had to hardcode stuff that should be processed (s.a.w value changing, m.s.i. formatting with square brackets). So it may work here, but not elsewhere yet.
 * re values used. Which Standard atomic weight (s.a.w.) to use? See Template:standard atomic weight documentation: shows the formal CIAAW values.
 * CIAAW (IUPAC) publishes the standard atomic weights: zero or one for each element. Each one can come in three values: std atomic weight, abridged (derived), conventional (derived). It allows us to use the "formal-short" form (for each element: use the shortest of the three). All fine.
 * That "short-formal" form may look like $1.008$ (H), $4.003$ (He) or $40.078$ (Ca). That is: up to 5 digits, no []-interval, when uncertainty is (1) it's noted implicit (not absent), or else noted explicitly like (4). So far IUPAC.
 * Now to shorten the values even further, to keep cell width small, in Periodic table/sandbox I have cut all uncertainties (so for Ca, (4) ). *This* is where we change the value IUPAC has defined. Do we want that?
 * Sidenotes about s.a.w.: (1) Wikidata does not have the right numbers (using PubChem as a source not IUPAC?). (2) this nice disciovery has different rounding (six digits); I'd say that is not desired.


 * re cell formatting: symbol now bold. To consider: put Z to the left of symbol? Below symbol?
 * Once we find this sandbox a bit stable, we can go to WT:ELEM I'd say. Hope to improve the boilerplate backgrounds one of these days. -DePiep (talk) 13:11, 6 March 2018 (UTC)
 * I add: a short descriptive note or link should be added; Periodic table (standard atomic weight) has (BTW, that one shows the short-formal values). -DePiep (talk) 13:49, 6 March 2018 (UTC)


 * I like the current sandbox version, except that I do not think the period numbers should be circled (the difference in font is distracting, and it is not standard practice). Cutting uncertainty is fine; it's what the Sargent-Welch periodic table chart does too, after all. We can discuss Z placement separately; the important thing here is to put in the atomic weights. Double sharp (talk) 12:05, 13 March 2018 (UTC)
 * OK, prepared to go live, needs some checks. We neeed ã text at the bottom. Linking to s.a.w. article.
 * BTW, those big-cell PTs heva gotten a major update today. -DePiep (talk) 18:57, 13 March 2018 (UTC)
 * Thank you very much! Double sharp (talk) 07:26, 15 March 2018 (UTC)
 * Thanks! Took four months.... Anyway, next step: add elconfig to those Large Cell PTs? Valences, big and small? See you. - DePiep (talk) 00:18, 16 March 2018 (UTC)
 * Electron configurations would be great, yes. (For Mt onwards we could perhaps grey them out to show that they are for now only predicted.) Valences, I think, should wait until we have some agreement on what species we are going to count (I intend to write about this one on WT:ELEM today or tomorrow). Double sharp (talk) 08:00, 16 March 2018 (UTC)

✅ - DePiep (talk) 01:00, 16 March 2018 (UTC)

Ionization energy
I am so surprised I can't find the real trend of ionization energy ( Increasing ........) in a popular encyclopedia like Wikipedia it's somehow not helpful   Basit olami (talk) 05:20, 22 March 2018 (UTC)
 * See Periodic table. Double sharp (talk) 07:26, 22 March 2018 (UTC)

“Nonatomic” nonmetals
Currently, in the Grouping methods § Metals, metalloids and nonmetals section, in the sentence “Nonmetals may be simply subdivided into the polyatomic nonmetals, being nearer to the metalloids and show some incipient metallic character; the essentially nonmetallic diatomic nonmetals, nonmetallic and the almost completely inert, nonatomic noble gases.” there is a typo. Nonatomic should really be monatomic (due to single —not zero— atoms in their molecules). 46.191.189.205 (talk) 17:03, 19 April 2018 (UTC)
 * Corrected. Burzuchius (talk) 17:12, 19 April 2018 (UTC)

Synthetic Elements
The table here gives plutonium as the heaviest natural occurring element and everything heavier as synthetic

https://en.m.wikipedia.org/wiki/Synthetic_element

Gives Einsteinium as the lightest synthetic element

Which one is wrong? or at least the apartment discrepancy needs to be clarified GramlerGrindstone (talk) 15:59, 23 June 2018 (UTC)
 * Synthetic element is wrong; I have changed it back. Although John Emsley's Nature's Building Blocks (2011) makes the assertion that Am, Cm, Bk, and Cf occur naturally, there do not seem to be any other sources supporting this assertion (that didn't take it from Emsley, or us when we were citing him). Double sharp (talk) 16:43, 23 June 2018 (UTC)

Optimal form subsection

 * I removed a "Citation needed" tag from the subsection. The reasoning is that there is a "Note" reference (n18), that shows to go to "Periodic table#cite_note-183", that is referenced twice (#164 and #165).
 * While I am not a fan of this form of citations, note #18 actually being reference #183 but because the numbering stops at #165 (confused yet?) but really that is not how the notes correspond, but unless someone wants to submit that text-source integrity is the issue ("not in citation" etc...) then to me there is ample evidence of sourcing.
 * I am also not a fan of using a "Bibliography" section for sourcing because it is confusing (MOS:BIB), since there is already a place at the beginning of the appendices for works or publications that can also be used for "Bibliography", "Discography", or "Filmography". I don't think I would see as much of an issue if it ("Bibliography") was placed as a subsection of "References", "Notes", etc..., however, there does appear to be referencing. Otr500 (talk) 01:48, 22 July 2018 (UTC)

Thanks for removing that "Citation needed" tag. I made the "Bibliography" a subsection of "References" as you suggested. The metalloid article is structured the same way. Sandbh (talk) 07:34, 22 July 2018 (UTC)
 * And thank you. I have been struggling with the "traditional" use of "Bibliography" as a section in the appendices per MOS, and using it as a sourcing section related to citations. My interest was that if the MOS is going to be broadly ignored then this might need to be examined. A bibliography, when associated with sources, becomes part of the citations so the general use is not an issue as much as placement as a separate section.


 * In cases on articles up to C-class I would simply convert the section to a subsection. I randomly picked over 60 articles (GA and FA only) and found 6 with a "Bibliography" section related to references. That seems to indicate that it is an "exception to the rule". When bibliography is used as sourcing it appears to be used more as a subsection, or sometimes bolded within a section which would be consistent with the definition. Have a nice day,  Otr500 (talk) 02:46, 23 July 2018 (UTC)

A recommendation
I suggest adding the three versions of the periodic table by Sargent-Welch as I find it very comfortable to read, very didactic, and very easy to understand (as best I can as I'm not a chemist or a chemistry student). 79.181.129.128 (talk) 12:37, 2 October 2018 (UTC)
 * They look great indeed. Already Periodic table (large cells). Could you tell what makes those sargentwelch periodic table so great? -DePiep (talk) 18:42, 3 October 2018 (UTC)

"Electron configuration" in the opening sentence
made a good faith edit in which "electron configuration" was removed from the opening sentence of this article.

The sentence in question originanlly read: "The periodic table of elements, usually shortened to just the periodic table is a tabular arrangement of the chemical elements, ordered by their atomic number, electron configuration, and recurring chemical properties, whose structure shows periodic trends."

Before I reverted, it read: "The periodic table of elements, usually shortened to just the periodic table is a tabular arrangement of the chemical elements, ordered by their atomic number, electron configuration, and recurring chemical properties, whose structure shows periodic trends."

I think knowledge of electron configurations enabled the leap from Mendeleev's periodic table to modern forms of periodic table. In particular, I recall that electron configurations enabled scholars of the day to resolve the knotty problem of where to place the lanthanides and, later, on, it supported the relocation of the actinides away from the the 4th row of transition block, to underneath the lanathanides.

At least for these reasons I reverted De Piep's edit. Sandbh (talk) 01:48, 7 October 2018 (UTC)
 * OK, elconfig did determine positioning of some elements indeed. I note that it also casused the combining of two Reihe into one period (A/B valence groups). -DePiep (talk) 08:26, 7 October 2018 (UTC)
 * ...But of course the main order is by atomic number only. Elconfig does not alter that. -DePiep (talk) 08:43, 7 October 2018 (UTC)
 * Not necessarily; Pyykkö's version of the extended periodic table puts elements out of atomic number order on the basis of electron configurations. Double sharp (talk) 12:22, 7 October 2018 (UTC)

Page views
Look at this. After Jan 8 (PT=FAT), visits re Periodic table doubled. (30k/day today, wow). -DePiep (talk) 21:48, 19 October 2018 (UTC)

Semi-protected edit request on 24 October 2018
Element 22 is not Erbium, it is Titanium (Ti). Erbium is Element 68, as it is duplicated in both slots 22 and 68. Jshmn (talk) 02:09, 24 October 2018 (UTC)
 * Yes check.svg Done, thanks for pointing out the vandalism. &#8209;&#8209; El Hef  ( Meep? ) 02:17, 24 October 2018 (UTC)

The elements
Does the name "periodic table of the elements" refer to chemical elements, or to "elements" as the world around? If it's the former, why doesn't the name include the word "chemical"? WikiArticleEditor (talk) 06:41, 13 January 2019 (UTC)

Semi-protected edit request on 5 February 2019
49.146.32.196 (talk) 12:49, 5 February 2019 (UTC) I REQUEST THERE IS A WRONG SENTENCE IN "The organization of the periodic table can be used to derive relationships between the various element properties, and also to predict chemical properties and behaviours of undiscovered or newly synthesized elements." and it is not as it said so!
 * Red question icon with gradient background.svg Not done: it's not clear what changes you want to be made. Please mention the specific changes in a "change X to Y" format and provide a reliable source if appropriate. &#8209;&#8209; El Hef  ( Meep? ) 15:28, 5 February 2019 (UTC)

Semi-protected edit request on 1 March 2019
Because this sentence is very hard to read because of its strange order, please change

Following the discovery, in 1911, by Ernest Rutherford of the atomic nucleus, it was proposed that the integer count of the nuclear charge is identical to the sequential place of each element in the periodic table.

to

Following the discovery of the atomic nucleus by Ernest Rutherford in 1911, it was proposed that the integer count of the nuclear charge is identical to the sequential place of each element in the periodic table.

Only the first part is changed, and I think the sentence is much clearer like that. 128.130.235.197 (talk) 15:49, 1 March 2019 (UTC)
 * Yes check.svg Done I agree; the initial sentence construction was a little convoluted. NiciVampireHeart 15:58, 1 March 2019 (UTC)

Semi-protected edit request on 25 March 2019
Maxwell1212q (talk) 16:54, 25 March 2019 (UTC)can i edit this partticular piece of writing please i think its incorrect and im going to add extra detail to it
 * X mark.svg Not done Please propose your change with the format "Change X to Y". Edit requests are not for general requests. 331dot (talk) 17:02, 25 March 2019 (UTC)'''

Semi-protected edit request on 21 August 2019
2019 will be the 150th anniversary since Dmitry Mendeleev discovered the Periodic System and has been proclaimed the "International Year of the Periodic Table of Chemical Elements" (IYPT2019)by the united nations organization Andrewandandrew (talk) 14:41, 21 August 2019 (UTC)


 * Red question icon with gradient background.svg Not done: it's not clear what changes you want to be made. Please mention the specific changes in a "change X to Y" format and provide a reliable source if appropriate.
 * Also, there is already some information on this in the article; if you have an addition, please make another request specifying exactly what you would like to add. ComplexRational (talk) 16:22, 21 August 2019 (UTC)

Last element to have a compound
What is the last element to have a compound?Porygon-Z 20:16, 7 March 2019 (UTC) — Preceding unsigned comment added by Porygon-Z474 (talk • contribs)
 * From what I can find, either hassium (HsO4 is described in that article) or copernicium ( suggests that CnSe was formed, though I would like another editor's opinion on this) is the heaviest element for which a compound has been synthesized. ComplexRational (talk) 20:34, 7 March 2019 (UTC)
 * The formation of nihonium hydroxide (NhOH) is a likely explanation for some 2017 results aimed at probing Nh chemistry, but is not confirmed (see Nihonium). I'd consider the paper on Cn to be enough to say that reaction with Se was observed; the product is then likely CnSe. Currently in copernicium we mention that producing this was the aim of the experiment. (And maybe this will be tried for Fl as well?) Double sharp (talk) 16:28, 21 August 2019 (UTC)

Semi-protected edit request on 31 August 2019
2A02:C7D:9E3E:7800:6A9A:87FF:FED0:4CBA (talk) 18:31, 31 August 2019 (UTC) bb
 * Blank requests cannot be considered. 331dot (talk) 18:44, 31 August 2019 (UTC)

Not getting the picture
I'm not happy with File:ShortPT20b.png being in here. It mixes up old (1871) and new (category colors) features. What is it supposed to illustrate?

If we want to illustrate changes from 1871, let me push Periodic table (Reihen and periods): showing on the "short" to "long" form. (that is, IMO: Mendeleev's 8-group to 1930?'s 18-group form). -DePiep (talk) 20:38, 4 October 2019 (UTC)

I add: Seaborg's 32-column form, usually shown with a bottom box of some 30 LN and AN elements, originates from ca. 1940. Which, in tihis image, is a weird -- and not consistent -- construction (a 1940 Seaborg form mixed with the short 1871 form?). -DePiep (talk) 20:41, 4 October 2019 (UTC)
 * Well, this picture is the layout a modern 8-column table takes: they are still used, especially in Russia. Double sharp (talk) 20:48, 4 October 2019 (UTC)
 * You mean 8-column 8-group, of course. VIII actually. -DePiep (talk) 20:53, 4 October 2019 (UTC)
 * I second Double sharp's comment. This is still the common periodic table form around here. This is what it will look like if you want to buy a poster with one or enter a school chemistry classroom. It is only in university and academic textbooks/papers that you could meet a 18 column table at all.--R8R (talk) 20:58, 4 October 2019 (UTC)
 * All fine, but why would we use the image here in an FA? It is wrong, unhelpful and useless. -DePiep (talk) 21:03, 4 October 2019 (UTC)
 * (ec) There is no reference from the main table to the bottom box (say, the    we know).
 * The category background colors do not add information. They distract.
 * Group 0 (18) is missing
 * It uses lowercase A/B in "a III b"
 * All in all it mixes up dated forms inconsistently (inherently so I say: because of the mixup)
 * Again I dare asking: what is it supposed to illustrate? -DePiep (talk) 21:01, 4 October 2019 (UTC)
 * Again I dare asking: what is it supposed to illustrate? -DePiep (talk) 21:01, 4 October 2019 (UTC)


 * From what I've seen, the period 6, group 3 spot is always filled with "La*". Sandbh used the atomic numbers, it seems clear enough to me, but if you like, you could change it, say, to what I have just described.
 * You're right, struck it. DePiep
 * How so? It's right there, right after the halogens. I have only seen "group 0" in person once, in a very old table.
 * I see: noble gases are in group VIII (WTF, are we serious?). DePiep
 * Yes. Noble gases are always in group VIII nowadays. In an older fashion, they were separated from group VIII metals (run a Google image search for "таблица менделеева" if you're curious about this, you can find some examples), but still were a part of group VIII. I cannot imagine a chemist that would in all seriousness argue that in the modern nomenclature the noble gases should not be in group VIII.--R8R (talk) 09:30, 5 October 2019 (UTC)
 * I think it doesn't matter?
 * lowercase/uppercase: yes it does. These are group names. How is this irrelevant? See also the "why" question. DePiep
 * Okay, I'll say it with more confidence then. I think it doesn't matter. And I think so because there is no information encoded in capitalization of these letters. It is important that some letters are capitalized in actual texts (which is explained by grammatical rules of each individual language), it is important in some coding languages, which accept "PRINT" and not "print" as a command or vice versa, it is important for passwords (duh). But there is no difference between group VIIIa and group VIIIA. "Group VIIIA" is not a proper noun.
 * The difference that one could point out is with groups A and B. In fact, there are two different ideas on what is a group A and a group B. One is that A is the main-group elements and B is the transition metals; one is that A is the first row in the period and B is the second. Both are used, both are okay.--R8R (talk) 09:30, 5 October 2019 (UTC)
 * I don't mean to be neglectful but I am missing your point here. Could you elaborate?
 * The image graphically does not represent the periodic table we know today, nor does it represent a truthful comparision/merge of any PT's back in time correctly. It mixes up forms & years inconsistently. DePiep
 * But it does represent the table we (well, I) know today! And that's precisely what I've been trying to point out.--R8R (talk) 09:30, 5 October 2019 (UTC)
 * Sandbh's original intention, if I recall correctly, was to demonstrate the original 8-group table updated to the present day. But we can summon to make sure. It makes good sense, I suppose, given that it is still in widespread use in its country of origin. So, a table just alright, colored just like our usual table.--R8R (talk) 21:15, 4 October 2019 (UTC)
 * (ec)If that was the intention, fine, but it did not work out well. (Let me push Periodic table (Reihen and periods) once more, but not yet for placement in this article). So we better face reality: not fit for article. DePiep
 * You did not reply to my main point: what is this image supposed to illustrate? (and to be honest: "used widespread" is inaccetable, don't we think?). -DePiep (talk) 21:43, 4 October 2019 (UTC)
 * This table, as it is, is the 8-group form commonly used today. In the article, it illustrates that Mendeleev's original 8-group format is alive and well and can be easily adapted to the contemporary reality, but in theory, it could also illustrate the point that it is still in actual widespread use today in its country of origin in the "Alternative layouts" section.--R8R (talk) 09:30, 5 October 2019 (UTC)


 * Well, given that this table shows all elements up to 118, perhaps it should be under "Alternative periodic tables" with some explanatory text about how the 8-group format is still common in Russia, rather than under "History" where it presents something of an anachronism. But it definitely deserves a place in the article precisely because it is still common – and indeed, pretty useful and not wrong, as what Mendeleev saw connecting the A and B groups is pretty real. Double sharp (talk) 21:33, 4 October 2019 (UTC)
 * It is wrong: noble gases in group VIII, for starters. Mendeleev about --later-- A and B: it's in his Reihen (2 Reihen make one group, roughly). Why in this article??? "widely used" is not that encyclopedic, better start Incorrect periodic tables. And once more: what does it illustrate? -DePiep (talk) 22:29, 4 October 2019 (UTC)
 * The noble gases used to be shown in group 0, but after synthesis of their compounds they came to be shown in group VIIIA. See, for example, (1975). Burzuchius (talk) 09:06, 5 October 2019 (UTC)
 * This is not supposed to be Mendeleev's table, which is already illustrated. It is supposed to be the modern form of the 8-group table as is widely used in Russia (with noble gases in group VIIIA), and illustrates that perfectly. (I wonder if the other post-Soviet states use it too?) Double sharp (talk) 11:06, 5 October 2019 (UTC)
 * Simply for the purposes of completeness of the discussion, while noble gases are indeed much more common to be VIIIA than VIIIB, I have seen a table or two that have the noble gases in VIIIB. I even had one of such tables in my school (though the other two had the usual A--B distinction). (As for the question re other post-Soviet states, I suppose that this cannot be true for the Baltic states, who were keen to adopt Western standards of everything as soon as possible. Out of curiosity, I ran a Google Image search for the Ukrainian and Georgian titles of their periodic table equivalents. The Ukraininan tables are predominantly 8-group, whereas the Georgian tables are actually difficult to encounter, but the three I found were all 18-column.) --R8R (talk) 14:41, 5 October 2019 (UTC)
 * Apparently Andreas von Antropoff suggested VIIIB for the noble gases before any noble gas compounds were known: see 10.1002/anie.198804791 and the noble-gas chapter of Greenwood and Earnshaw. (I just searched Kazakh and Lithuanian: as expected, Kazakh shows a majority of 8-group, while Lithuanian shows a solid majority of 18-column. Though apparently in both languages it can also be called the Mendeleev table as well. Incidentally, I checked Lithuanian because last year I noticed that they were missing an article for Ts and wrote in a brief stub with the help of copy-and-paste, Google Translate, and some guides on Lithuanian grammar. :-D It's been corrected since.) Double sharp (talk) 16:02, 5 October 2019 (UTC)

I drew this table when the article was being put up for TFA the second time. I recall R8R requested it, and that R8R "approved" it. It is supposed to illustrate what a modern short table would look like, with our colour categories. The Russian wikipedia also shows this table, here. Sandbh (talk) 07:05, 5 October 2019 (UTC)
 * Unfortunately, I genuinely don't remember this occurring and for this reason alone cannot confirm this, but if I did approve it, then I stand by my approval.--R8R (talk) 14:41, 5 October 2019 (UTC)


 * Somehow, this thread is complicated, confusing, and touching persons. Even worse: it does not reflect our cooperative sense I know so well from WT:ELEMENTS. (The cause could be me). So I prefer to leave this thread for a week. Then I will come back, reread it all, and make this wiki better, especially our PTs. My talkpage is open. -DePiep (talk) 18:29, 5 October 2019 (UTC)

error in denoting the elements
In this article polonium is denoted as post transition metal but it is a metalliod while astatine is denoted as metalliod at the place of polonium. In this article hydrogen is denoted as alkali metal but it is in s block element due to its atomic number and electronic configuration. Hgdf fdgh (talk) 15:07, 21 January 2020 (UTC)


 * As for hydrogen, what do you mean? It is consistently shown as a nonmetal. In a general discussion, it is explicitly said that "hydrogen has no analogs and is not considered to be an alkali metal as it rarely exhibits behaviour comparable to that of the alkali metals."
 * As for polonium and astatine, I recall there was a discussion a while ago at Wikipedia talk:WikiProject Elements that concluded on that properties of polonium are best summarized by classifying Po as a post-transition metal and similarly, that properties of astatine show that At should be listed as a metalloid. Since I dug through literature a while ago to see the properties of astatine, I will immediately fully agree with the latter assessment.
 * So everything looks fine unless you can bring up a good argument it is not.--R8R (talk) 15:19, 21 January 2020 (UTC)

The La-Ac vs Lu-Lr in Group Three
I think the chemistry community is leaning towards Lutetium and Lawrencium being in the third group of the periodic table with f-block in between group two and group three (please refer to the image provided). This is going to be a big change to all Wikipedia chemistry pages, but it is necessary to correct the information according to new studies, Wikipedia is one of the only websites that still use La-Ac in the third group. I myself doesn't have the ability to make changes, so if the change can be made that would be great. --AnthonyDu0122 (talk) 02:07, 1 March 2020 (UTC)
 * Hello, and welcome to Wikipedia. This is actually one of the most heavily debated topics at WikiProject Elements, so I'm glad you brought it up here. I myself have not been very active in such discussions, but I have a general idea of the arguments for La-Ac vs. Lu-Lr. There are several extremely long discussions on the subject, one of which is active: Wikipedia talk:WikiProject Elements (active, with some recently archived portions at Wikipedia talk:WikiProject Elements/Archive 42); Wikipedia talk:WikiProject Elements/Archive 38 (a few months old); Wikipedia talk:WikiProject Elements/Archive 33 (two years old); Template talk:Periodic table (a rather older RfC in which consensus is established for Sc-Y-La-Ac); and there are a few even older ones in the talk page archives. Do you have sources for these "new studies" you mention? If so, I advise you to drop by the project talk page and state your reasoning, but it may be better to directly address one of the editors more involved in this discussion ( and may offer some useful insight). ComplexRational (talk) 02:43, 1 March 2020 (UTC)
 * I sympathise with the idea that Sc-Y-Lu-Lr is the "right table" indeed, but we're supposed to be following the literature and not going ahead of it on WP. Historically, Sc-Y-La-Ac was indeed the more popular form, and it's still pretty common (unfortunately in my current opinion). If IUPAC makes the ruling for group 3 as Lu-Lr, then that would definitely be enough to revisit the close and switch to Lu-Lr. It would also be enough if more modern books start making the switch en masse, which may well happen or have happened already. Did you know that Clayden, Greeves, and Warren's Organic Chemistry 2nd edition has a Sc-Y-Lu table? ^_^ We could presumably count up and see the trends. Could you link me to the "new studies" you're mentioning?
 * (Now we just need to get more people to listen to Bent and Grochala about how the "right table" should have helium over beryllium. ^_^) Double sharp (talk) 10:57, 1 March 2020 (UTC)

Minor suggested edit
The first sentence in the second paragraph after the large table diagram at the top of the article body reads "In the standard periodic table, the elements are listed in order of increasing atomic number Z (the number of protons in the nucleus of an atom)." I propose to delete the final parenthetical phrase, as Z is already defined immediately previously, and described as number of protons in the previous paragraph where Z is first referred to. 72.92.54.85 (talk) 01:07, 28 April 2020 (UTC)
 * Done. Indeed, rm repetition. -DePiep (talk) 11:28, 28 April 2020 (UTC)

the IUPAC
re : I can get that, but something is missing. When/why does one *not* write "the Mexico introduced a law ...", "the New York City decided ..."? What is the bigger rule? -DePiep (talk) 19:47, 6 March 2020 (UTC)
 * As it happens: "Containment of virus is world's 'highest priority', says WHO" . -DePiep (talk) 20:16, 6 March 2020 (UTC)
 * I am fully confident that, in a sentence, it's "New York City is a city in the United States" and "the City of New York is a city in the United States". Also not "the Mexico" but "the United Mexican States." I'm rather puzzled myself why it's this way; seems right mostly because of how much English I've seen/heard, but I can't convincingly explain the difference. Acronyms are different, and not even all native speakers get this, really, I've tried to find that out myself and seen puzzled native speakers in language forums.
 * would you mind lending us a hand here and explain why this works in English the way it does?--R8R (talk) 20:26, 6 March 2020 (UTC)

I always thought the rule was that you use the article if the acronym hasn't already sort of become a name (like "IUPAC", since people read it as a word) and you would use it if the acronym was expanded out into words (that's why I thought it should have been "the JINR", as in "the Joint Institute for Nuclear Research"). Alas, I have no source for that, and maybe that is not universally agreed. Double sharp (talk) 05:50, 17 May 2020 (UTC)

Error in naming of group 1
Now (2019-12-25 20:38 CET) it says "Alkali metals" on group 1. This is not correct since Hydrogen is not a alkali metal. Therefore, the correct naming, if there shall be a naming of group 1, it shall be "H and alkali metals". It even says so under Hydrogen own page on wikipedia https://en.wikipedia.org/wiki/Hydrogen — Preceding unsigned comment added by 85.195.49.240 (talk)
 * Well, this seems to be fixed already.
 * Really, we would be better off abandoning the idea that a family should expand to include the whole of a group. Calling Og a noble gas is almost certainly ridiculous, calling At a halogen is already equivocal, and Be and Mg are rather bad alkaline earth metals for the simple reason that they are not alkaline. But unfortunately we have to follow what the sources usually do here. Double sharp (talk) 05:52, 17 May 2020 (UTC)

A relevant argument, unfortunately incomplete in sources
I wrote this paragraph, but then deleted it: Because of the almost completely regular variation of lattice and solvation energies across the lanthanide series, the most important factor determining redox stability of lanthanide compounds is the third ionisation energy. This almost always involves the loss of one f electron, for which ligand field stabilisation energies are negligible as the f shells are deeply buried; that is distinct from the behaviour of the d transition elements. In almost all cases this ionisation is M2+ (4fn) → M3+ (4fn−1); although lanthanum (La2+ [Xe]5d1) and gadolinium (Gd2+ [Xe]4f75d1) are exceptions, the regular configurations [Xe]4f1 and [Xe]4f8 are very low-lying excited states (energies 0.8881 eV and 0.295 eV) respectively that negligibly affect the ionisation energy trend on being subtracted (the third ionisation energies of La and Gd respectively are 19.1773 eV and 20.63 eV). Similar processes are observed for example in the condensation of the lanthanides, which generally involves the transition 4fn6s2 → 4fn−15d16s2 and so varies in energy similarly to the above 4fn → 4fn−1 ionisations. In condensed phases the configurations of the Ln2+ may also change due to smaller destabilisation of the 5d orbitals compared to the 4f by ligand field effects. Energy variation of a process across the lanthanide series can be predicted from how the number of 4f electrons changes during its reactions. However, lutetium cannot be considered to be of this type as an f shell cannot hold the 15 electrons that would be required. Similarly, if we consider the processes where it is the relative stability of M3+ and M4+ that is at stake, then lanthanum cannot be considered as getting it to the +4 state would require breaking open the xenon core. (cite Johnson from the article)

The problem is that this argument, so far as it is taken in the source, does not clearly support either La-Yb or Ce-Lu as the 4f row. (Of course, there are lots of arguments about why La-Yb is the right answer and why the arguments for Ce-Lu are focusing on chemical irrelevancies in the literature. I know it probably doesn't look like the periodic table in your textbook, but (1) that textbook is probably not focusing on group 3 and (2) if you can cite Seaborg, as well as Landau and Lifshitz, on your side, like I have, it's definitely not a fringe view. XD) In order to make it complete, you would have to note that physical properties universally support the +2 to +3 process' double periodicity, but so far I haven't seen that being noted. Which is admittedly a bit puzzling, because it is absolutely obvious from the cited values of melting and boiling points: minima occur at Eu and Yb, just as they do at Mn and Zn. Double sharp (talk) 04:44, 18 May 2020 (UTC)


 * Deleting it was a good move.


 * Johnson: The relevance of his reference to the third ionisation energy involving the loss of one f electron in the free atom, is puzzling.


 * The Ln metals, as opposed to the free atoms, are mostly f1-14d1s2. In their most stable trivalent cationic forms they are f1-14. Here, Ce3+ is f1, Pr3+ is f2, ending with Yb3+ f13 and Lu3+ f14. Thus, the f-block metals and their cations run from Ce-Lu. La is not include in the particular set, since La3+ is [Xe] i.e. it has no f electron.


 * As Seaborg wrote, "it is the electronic structure of the ions and compounds that we are chiefly concerned with in chemistry".


 * Seaborg again: An examination of Seaborg's article on the development of the actinide hypothesis shows he consistently distinguished between La-Ac, and Ce-Lu, Th-Lr. See figures 2, and 4-6 (pp. 52, 54-56).


 * The right answer: There are no arguments about why La-Yb is the "right" answer. Rather, there are some arguments in the literature suggesting La-Yb looks better in some cases. Many of these are one-shots based on a single property. Jensen had a red-hot go at corralling these arguments in 1982, in support of La-Yb, but his effort failed to gain traction. He was criticized by Scerri, (chair of the IUPAC Group 3 project group) and Parsons (2018, p. 143), for being too selective in his arguments. There was Holden (1985) who looked at seven properties but estimated the argument of Landau & Ligshitz (1958) to be the strongest. For a discussion as to the unreliability of Landau and Lifshitz, see here.


 * A survey by the IUPAC Group 3 project team found that the majority of textbook and other periodic tables in the 18-column format show the elements of group 3 as scandium, yttrium, lanthanum and actinium. The survey did not include a Google image search, since such results are plagued by bias arising from the false impression that the IUPAC *-** table is “official”, and unreliable sources.


 * Mathias (1969) grumbled about La in group 3 being the most popular form. Myers, Oldham and Tocci (2004, p. 130) found La and Ac to be the most popular form of periodic table, a sentiment echoed by Clarke and White (2008); and Lavelle (2008; 2009).


 * Clark RW & White GD 2008, "The flyleaf periodic table", Journal of Chemical Education, vol. 85, no. 4, p. 497
 * Holden NE 1985, Status of the lanthanides and actinides in the periodic table, accessed 24 November 2016
 * Jensen WB 1982, The positions of lanthanum (actinium) and lutetium (lawrencium) in the periodic table, Journal of Chemical Education vol. 59, pp. 634−636
 * Lavelle L 2008, "Lanthanum (La) and actinium (Ac) should remain in the d-block", Journal of Chemical Education, vol. 85, no. 11, pp. 1482–1483, doi: 10.1021/ed085p1482
 * —— 2009, "Response to misapplying the periodic law", Journal of Chemical Education, vol. 86, no. 10, p. 1187, doi: 10.1021/ed086p1187
 * Mathias BT 1969, "Systematics of superconductivity", in PR Wallace (ed.), "Superconductivity: Proceedings of the Advanced Summer Study Institute on Superconductivity", McGill University, Montreal, vol. 1, Gordon and Breach, New York, pp. 225−294
 * Myers RT, Oldham KB & Tocci S 2004, Holt chemistry, Holt, Rinehart and Winston, Orlando
 * Scerri ER & Parsons W 2018, "What elements belong in Group 3 of the periodic table?". In E Scerri & G Restrepo (eds), Mendeleev to Oganesson: A multidisciplinary perspective on the periodic table, Oxford University Press, New York, pp. 140–151


 * Chemical irrelevancies: There are no arguments in the literature, to my knowledge, saying Ce-Lu is focusing on "chemical irrelevancies".


 * Double periodicity: As to Eu and Yb, and Mn and Zn, it is more relevant, from a chemistry based view, rather than a physical property-based view, to note double periodicity for the 4f and 3d metals pivots around Gd and Lu, and Mn and Zn.


 * Shchukarev (1974, p. 118), a well-regarded Russian chemist, supported -La-Ac on the grounds that the 4f shell does not start filling until cerium and that (effectively) the filling sequence—which runs from cerium to lutetium—is periodic, with two periods. Thus, after the occurrence of a half-full 4f shell at europium and gadolinium, the filling sequence repeats with the occurrence of a full shell at ytterbium and lutetium (Rokhlin 2003, pp. 4–5). A similar, but weaker, periodicity (Wiberg 2001, p. 1643–1645) is seen in the actinoids, with a half full 5f shell at americium and curium, and a full shell at nobelium and lawrencium.


 * Placing lutetium and lawrencium under yttrium obscures the start of the filling of the f-block (it would appear to start at lanthanum) and visually truncates its double periodicity (it would be cut off at ytterbium whereas it would actually end in the d-block). In Shchukarev’s words, the "correctness of placing of imitators before gadolinium and curium as well as lutetium and lawrencium, would be lost. The exceptional uniqueness of Gd and Cm, akin to that of Mn and Zn, would also be unclear."


 * Here is what a lanthanum table looks like:

+4            +2    | +4             +2 Ce Pr Nd Pm Sm Eu Gd | Tb Dy Ho Er Tm Yb Lu                ½f ½f |                f  f                      | +4            +2    | +4             +2       Th Pa U  Np Pu Am Cm | Bk Cf Es Fm Md No Lr                     ½f ½f                  f  f


 * Shchukarev’s imitators are Eu2+ and Yb2+ which like to attain the Gd3+ and Lu3+ cores. Then there is Ce4+, which likes to attain the core of its lanthanoid progenitor namely La3+; and Tb4+ attaining the same configuration as Gd3+.


 * Europium, the most reactive of the lanthanoids, is associated with the place of a halogen, and gadolinium is associated with place of a noble gas, although to a much lesser degree. See the Rare-earth metal long term air exposure test (Hamric 2007). Terbium to lutetium are much less reactive, and the Group 17/18 analogy is not seen here.


 * The f-block contraction starts with Ce3+ and culminates in Lu3+.


 * The lutetium option is less regular:

+4            +2 |    +4             +2 La Ce Pr Nd Pm Sm Eu | Gd Tb Dy Ho Er Tm Yb                   ½f | ½f                 f                      | +4            +2 |    +4             +2       Ac Th Pa U  Np Pu Am | Cm Bk Cf Es Fm Md No                        ½f   ½f                 f


 * The ½-filled and filled f- sub-shell regularity is lost; the correspondence of europium and gadolinium to Group 17 and 18 metals is lost; the f-block contraction starts with Ce3+ and awkwardly finishes in the d-block.


 * Shchukarev’s approach is consistent with the observation of a progressively delayed start of filling of the f-shell as one goes down the periodic table i.e. at cerium for 4f; at protactinium for 5f although some 5f involvement may be possible for thorium (Edelstein & Kot 1993, p. 86); and at E123−125(?) for 5g (Eugen Schwarz, pers. comm. 8 Dec 2019).


 * This double periodicity had been noted by Klemm (1929; 1930) on the basis of atomic structure (Remy 1956, p. 492); and by Sobolev (2000, pp. 44–45).


 * Edelstein NM and Kot WK 1993, "Spectroscopic and magnetic studies of tetravalent Pa and trivalent Th compounds", Journal of Alloys and Compounds, vol. 193. pp. 82–87
 * Hamric D 2007, "Rare-earth metal long term air exposure test", Metallium, Inc., viewed 7 March 2020
 * Horovitz O & Sârbu C 2005, "Characterisation and classification of lanthanides by multivariate-analysis methods", Journal of Chemical Education, vol. 82 no. 3, pp. 473–483, doi: 10.1021/ed082p473
 * Klemm W 1929, "Measurements on divalent and quadrivalent rare earth compounds. II. A system of rare earths based on periodic property changes of their ions", Zeitschrift für anorganische und allgemeine Chemie, vol. 184, p. 345
 * —— 1930, "Measurements on divalent and quadrivalent rare earth compounds. IV. Supplement to the communication: A system of rare earths", Zeitschrift für anorganische und allgemeine Chemie, vol. 184, p. 29
 * Remy H 1956, Treatise on inorganic chemistry, vol 2, Elsevier, Amsterdam
 * Rokhlin LL 2003, Magnesium alloys containing rare earth metals: Structure and properties, Taylor & Francis, London
 * Sobolev BP 2000, The rare earth trifluorides: The high temperature chemistry of the rare earth trifluorides, vol. 1, Institut d'Estudis Catalans, Barcelona, pp. 44–45
 * Ternström T 1976, "Subclassification of lanthanides and actinides", Journal of Chemical Education, vol. 53, no. 10, pp. 629–631
 * Wiberg N 2001, Inorganic Chemistry, Academic Press, San Diego


 * Physical properties: Concluding with these, lutetium resembles the 5d transition metals more than is the case for lanthanum. That said, lutetium resembles closely erbium and holmium, and while it melts at a slightly higher temperature and is essentially non-magnetic, the details of producing, purifying and fabricating it are almost identical to that for holmium (Spedding et al. 1968).


 * Spedding FH & Beadry BJ 1968, "Lutetium", in CA Hampel (ed.), The encyclopedia of the chemical elements, Reinhold Book Corporation, New York, pp. 374–378


 * --- Sandbh (talk) 03:29, 19 July 2020 (UTC)

Caption wording
I changed changed a caption, using shorter but nearly synonymous wording to avoid unnecessary line wrapping. then reverted this, noting correctly that. I have now been made aware of an ambiguity. In my WP:ENGVAR, a person asked "How do you classify selenium?" might answer in any of these ways: Now (1) and (2) represent the sense I intended while (3) and (4) represent the sense that DePiep refers to as a change. I believe native speakers would probably think of the first sense, and most non-native speakers, given the context, would also understand that this is the sense intended. But perhaps the sense of (1) and (2) is not used in other ENGVAR. In that case I gladly accept the revert. But if I am correct, then I think the ambiguity is very slight and should be accepted in order to improve the line wrapping of the caption. YBG (talk) 15:13, 26 July 2020 (UTC)
 * 1) I classify it as a metal
 * 2) I classify if as a metalloid
 * 3) I classify it by considering its chemical properties
 * 4) I classify it by considering its physical properties.
 * do you mean this edit? ;-) Later more. -DePiep (talk) 19:41, 26 July 2020 (UTC)
 * Thank you, yes, that was the edit I meant. I have fixed it above. 21:47, 26 July 2020 (UTC)

so you changed
 * |,, , and in the periodic table. Sources disagree on the classification of some of these elements.

into


 * |,, , and Sources disagree on how to classify some elements.

All fine with me, and yes IMO the ambiguity is real ("classify as" vs. "classify by"). Anyway, I'm fine leving it here. -DePiep (talk) 22:04, 26 July 2020 (UTC)


 * When you say "all fine by me", I presume that means you're ok with my change, though you don't like it enough to restore it yourself. YBG (talk) 04:58, 27 July 2020 (UTC)
 * Yes as you write, I should have included your reply and my reversal. I wrote I'm fine with both forms because, more precise than my editsummary here I cannot discuss this orthography in classification. I'm not sure it is an ENGVAR thing, I think the wording is explicitly one way or the other (or it should be so). By now, Sandbh has responded with added a line of thought (below), and I hope this leads to fleshing out into a correct, unambiguous wording. -DePiep (talk) 09:25, 27 July 2020 (UTC)
 * Will pick up this, as there are some things I think I can say. -DePiep (talk) 09:55, 27 July 2020 (UTC)

It is not so much that they disagree. Rather, classifications may vary depending on the context i.e. criteria of interest. We don't have to worry about that since we go with the majority.

Scerri talks about it, here, when he says, "any system of classification must inevitably remain interest dependent" etc. Thus:


 * "Sources may vary in their classifications, according to interest dependence."

Or something like that.

--- Sandbh (talk) 08:05, 27 July 2020 (UTC)


 * The first description YBG gives appears correct to me (making a difference between (1),(2) "classify as" versus (3),(4) "classify by"). I don't think it is an ENGVAR issue, but more an imprecision in language or orthography (both are correct answers to "how do you classify ..."). Originally I preferred this ambiguity being resolved in our article, as it is a fundamental to the enwiki presentation of "categories".
 * Then, Sandbh leads to an encompassing form (catching all (1)–(4) meanings). In this case, a caption of a small image, this could be OK. In other situations, e.g. describing metalloids, the difference still may be important because there, classification is the topic. Maybe it needs to have a gradual scale of inclusion ("is more a metalloid"), even with a single interest approach. Our Lists of metalloids already does a grading scale, but by a generic, tallying scale not by an "interest" scale. (I note that recently we re-classified At which now follows this Lists' order: At and Po treated the same).
 * With this, I prefer Sandbh's proposal. It also prevents making a choice based on line wrapping. -DePiep (talk) 10:19, 27 July 2020 (UTC)


 * : what is you response to 's reply? I saw better solution. -DePiep (talk) 18:36, 27 July 2020 (UTC)
 * I had planned to incorporate his suggestion, but it proved too difficult to do on my smartphone. Hope to get to it soon. YBG (talk) 02:49, 29 July 2020 (UTC)
 * I have changed it to an aggressively abbreviated form of 's suggestion: YBG (talk) 02:28, 1 August 2020 (UTC)