Talk:Periodic table

Ambiguity regarding the positioning of Lanthanum (La) and Actinum (Ac) in the Periodic Table.

Hello! I believe that though we study La and Ac along with the F-block elements, they should be placed in the D-block as they have none and full 4f orbitals respectively. This makes them unfit for being in the F-block. Please do help me with this. Thanks, SSG123 (talk) 17:02, 6 November 2021 (UTC)

That is the so-called "Group 3" problem, discussed at Periodic table#Group 3 and endlessly on these Talk Pages and archives. It will be very difficult to undo the present consensus unless and until IUPAC make a ruling (and many will continue to disagree even then). Mike Turnbull (talk) 21:03, 6 November 2021 (UTC)

Thank You! SSG123 (talk) 06:36, 8 November 2021 (UTC)

There are a couple of things to consider.

1. In 1960, Sanderson (p. 8) wrote:

“If a d electron, for example, can easily behave like an f electron, or vice versa, the argument as to the exact ground state configuration becomes relatively unimportant.”

That is to say, given La is the progenitor of the lanthanides it seems to be the case that it can relatively easily behave as if it were an f element (as is the case with Lu) never mind its electron configuration of 5d¹6s² rather than the expected 4f¹6s².

• Sanderson RT 1960, Chemical Periodicity, Reinhold, New York

2. In any event, if the 4f row is shown as La to Yb, the number of f electrons in each atom corresponds to its position in the row, in all bar three cases (La, Ce and Gd). Whereas if the 4f row is instead shown as Ce to Lu, the number of f electrons in each atom corresponds to its position in the row in only three of 14 cases (Ce, Gd, Yb).

The situation in the 5f row, for Ac to No, is a little more complex, bearing in mind the earlier members show a decreasing resemblance to their transition metal congeners until the group 3 resemblance sets in.

If the actinide series is shown as Ac-No, it can be divided into three relatively cohesive sets:

• Ac and Th, which each have a number of d electrons equal to their position;
• Pa, U and Np, which have a mix of d and f electrons; and
• Pu to No, in which the number of f electrons in each atom corresponds to its position in the row in all cases except for Cm.

The position number and either d or f electron count matches in 10 of 14 cases.

If the actinide series is instead shown as Th–Lr, the three sets become discombobulated:

• Th, the first member, with two d electrons;
• Pa, U, and Np with a number of f electrons corresponding to their position in the row;
• Pu to Lr, in which only Cm and Lr have a corresponding number of f electrons.

The position number and either d or f electron count matches in 5 of 14 cases.

Conclusion: With Lu-Lr in group 3, the electron configuration “filling pattern” becomes easier to explain, and more consistent with quantum mechanics (QM) acknowledging electron configurations do not explain everything and that chemistry is not fully reducible to QM. Sandbh (talk) 10:40, 8 November 2021 (UTC)

Above notes updated. Sandbh (talk) 21:00, 13 December 2021 (UTC)

Error in ionization energy

I spotted a mistake in the section about ionization energy. Ionization energy increases “left to right and down to up”, and not “left to right and up to down” as in the current text 71.232.97.135 (talk) 02:33, 13 December 2021 (UTC)

 Done Yes indeed. I've made the change. Mike Turnbull (talk) 15:28, 22 December 2021 (UTC)

Periodic table of the elements

I’d like to be able to come to this site and be able to see a color coordinated list of the names of them. 135.134.173.151 (talk) 14:52, 22 December 2021 (UTC)

There are many way to color-coordinate the elements and one commonly-used way is shown at Periodic table#Classification of elements. Was there something else you had in mind? Many of the other tables in the article either explicitly name the elements or have links to them which show full names if you hover over them with the cursor. Mike Turnbull (talk) 15:18, 22 December 2021 (UTC)

A black-and-white periodic table image shows its main features best: columns=groups, rows=periods, rectangular units=blocks. Immediately recognisable! Any color coding would distract from this main setup. And after all, this is the introductionary image, no details have to be explained. However, when going into details and analysis, coloring can be very helpful. So there is: 1, 2, 3. -DePiep (talk) 08:32, 9 January 2022 (UTC)

18-column form needed as the lede table

Consistent with what DePiep noted above about a black and white v. coloured table, I suggest the periodic table in the lede should be an 18-column form rather than a 32-column form. The 18-column form is by far and away the iconic form widely recognisable around the world. In comparison, the 32-column form is obscure, non-representative of the literature, and in this context, undue. It should not be featured in the lede although it certainly warrants a mention later on in the article. An 18-column form would also be more legible. Sandbh (talk) 23:01, 9 January 2022 (UTC)

• @Sandbh: no, this is not "Consistent with what DePiep noted above". For starters, I invoke "... would distract from this main setup", "introductionary image, no details have to be explained", "shows its main features best" and "immediately recognisable!". And concluding, I say "[for] details and analysis, coloring can be very helpful" (italics added). -DePiep (talk) 06:49, 10 January 2022 (UTC)
• No. The 18-column format is a deformation, by non-scientific grounds even. We don't need an "iconic" form, we need the informative form. 18-column has a needeless complication: it is deconstructed, a deviation from the proper scientific periodic table. The icon is only helpful for initiated people like scholars (who immediately, intuitively and by excecise, understand and overlook the complications). But tallying published forms is not a sound base to reach a good encyclopedic result: you are polling the in-crowd. Those people are used to it. It started with Seaborg no less 80 years ago, when he needed to fork out the new discoveries as a block (and again, writing for high-end scolars). Scholars more easily could accept the books page-ratio limits (at the cost of extra studies, for example the exact border cases wrt group 3). By the way, since say 2000, webpages are available, overcoming such hard limits.

We are creating a general encyclopedia, and we do not require such proir knowledge, training or intuition. It's easy: After you've seen/grasped/recognised/learned the single-graph version, one can quite easily recognise & understand the forked graph. The opposite route, start by learning the scattered blocks, then reconstruct the full form in mind, is not obvious and requires extra mental steps to get the essence.

As an encyclopedia: there is no advantage in presenting a deconstructed form. -DePiep (talk) 11:00, 10 January 2022 (UTC)

@DePiep: Oh, what I meant by being consistent with you was where you wrote, “And after all, this is the introductionary image.”

Thus, the 18-column form is universally the introductory form in the literature. It matters not at all what your personal views are about how “bad” the 18-column form is. Not only that, the 18-column form has achieved the status of an icon in the Western world. As an encylopedia we are obliged to reflect the literature. Hence the periodic table in the lede should by an 18-column form, as adopted by the International Union of Pure and Applied Chemistry[1], the American Chemical Society[2], the Royal Society of Chemistry[3], PubChem[4], and ptable.com[5]. Sandbh (talk) 09:44, 11 January 2022 (UTC)

I wrote about being an introductionary image in relation to the coloring of details (ie, not useful in this introduction). As one can read. I did not write that being an introduction means there are no encyclopedic requirements. Agree with you that personal opinions don't matter, so it fits that I wrote that for encyclopedic reasons we should use the most helpful one. (Sandbh, next time please leave out the personal jab and the out-of-context misreading—esp when orig quote is nearby so easily to point out. iow: speak for yourself). -DePiep (talk) 15:05, 12 January 2022 (UTC)

I’m not a regular on this article but do have an interest. The main reason the 18 column version is published in so many locations is it’s easier to publish on 8.5x11” or A4 dimensions. It’s a matter of convenience, not preference, in other words. (Let’s just hope we don’t have to make room for the next row, which would likely be 50 columns, anytime soon!) Jtrevor99 (talk) 20:13, 12 January 2022 (UTC)

Mental states with the periodic table

• Understanding and appreciation of the Periodic Table should not require IKEA assembly manuals & skills

Mendeleev, 1871

1871–

Wikipedia reader trying to understand an 18-column periodic table

Early XXI century

Showroom Wikipedia: Featured Article

Periodic Table, 10k visitors per day

DePiep (talk) 20:02, 10 January 2022 (UTC)

Rfc about the periodic table in the lede

Should the periodic table in the lede be an 18-column table or a 32-column table? Sandbh (talk) 04:15, 20 January 2022 (UTC)

{@Sandbh}} Why at all do you call for Votes? How does that improve Comments & discussion, as WP:RfC defines & asks for? -DePiep (talk) 05:00, 21 January 2022 (UTC)

Votes

18: Reasons:

• The 18-column form is by far and away the most common form appearing in books as their lede table (often found on the inside cover).
• The 18-column form has achieved the status of an icon in the Western world.
• As an encylopedia we are obliged to reflect the literature.
• The 18-column form is used by the International Union of Pure and Applied Chemistry[6], the American Chemical Society[7], the Royal Society of Chemistry[8], PubChem[9], and ptable.com[10]. Sandbh (talk) 04:15, 20 January 2022 (UTC)

• 18 the 32-column table is too wide to have in the header on a mobile phone. The 18 wide form is fine though I do wish it was made more obvious where the Lantanides and Actinides fitted in rather than people having to look for the gap in the atomic numbers. The presentation forms in the article would be fine with details chopped out. Colours should be used too. NadVolum (talk) 09:39, 20 January 2022 (UTC)

• 18 - appearance on mobi matters to me as NadVolum mentions, and I also think it a better presentation plus better tutorial approach to begin with a simpler colourised version. Cheers Markbassett (talk) 01:04, 21 January 2022 (UTC)

Talk, notes, questions, suggestions

@NadVolum: The location of the lanthanides and actinides could be be made obvious by adding a column for them, as seem in the image. I feel that colors is something that should be the topic of a separate RFC, after this one. Sandbh (talk) 22:58, 20 January 2022 (UTC)

Conventional periodic table showing where the Ln and An fit in