Talk:Standard atomic weight

Changes to the standard atomic weights of 14 chemical elements have been recommended recently (), this should be incorporated into the article and values be updated accordingly. Szaszicska (talk) 21:26, 7 October 2018 (UTC)

Yes. Surprisingly, the "2017" changes were announced in June 2018. -DePiep (talk) 21:33, 7 October 2018 (UTC)

 Done. See {{Infobox element/symbol-to-saw/standard}} + its documentation. - DePiep (talk) 21:54, 7 October 2018 (UTC)

Conventional value for argon not published yet. Former abridged value looks suspicious. The 13 other changed values appear to be in same abridged bracket; waiting for publication. -DePiep (talk) 14:00, 8 October 2018 (UTC)

The sentence "In 2017, no changes were published." in the 1st paragraph under the "Published values" section needs to be revised with the publication of ^[1]

Slark (talk) 11:31, 2 February 2019 (UTC)

 Done. -DePiep (talk) 11:41, 2 February 2019 (UTC)

Cheers DePiep, the <ref> I cited above needs to be added to the text "2017" in the title for "Template:Standard atomic weight of the elements".

This <ref> also needs to be cited in the note column (with the note "2017") of the 14 elements whose standard atomic weights were revised in 2017 (13 Al, 18 Ar, 27 Co, 79 Au, 67 Ho, 77 Ir, 25 Mn, 41 Nb, 59 Pr, 91 Pa, 45 Rh, 65 Tb, 69 Tm, 39 Y).

▪ Please check the current value of the conventional atomic weight of argon: it is either 39.948 (https://www.isotopesmatter.com/applets/IPTEI/IPTEI.html) or 39.95 (https://applets.kcvs.ca/IPTEI/IPTEI.html and https://iupac.org/wp-content/uploads/2015/02/IPTEI_postprint_20190301.pdf, p. 47) – Alexander Lozovsky (talk) 12:52, 8 October 2019 (UTC)

@Alexander Lozovsky: I replied at talk:argon, where you have put the same post. -DePiep (talk) 13:45, 8 October 2019 (UTC)

About atomic weight's data we are using.

• The enwiki dataset is up to date with the latest CIAAW/IUPAC formal publications re Standard atomic weight (weight?). The local enwiki s.a.w. dataset (overview) reflects the 2013-2015-2017-2019 statements and changes, refs included.

• Recently, each Wikidata element's s.a.w. property has been updated, so today the WD and enwiki values are the same! -- that is: they are the IUPAC ones. See overview and compare wikidata (which calculates any delta). -DePiep (talk) 22:21, 20 October 2020 (UTC)

The physical quantity standard atomic weight (A_r) is dimensionless by definition. So: the value has no unit after the number.

Different is: physical quantity Atomic mass (m_a or m), it has unit: Da or u.

Lambiam tried to clarify this in this GF edit, but the wording was incorrect so I had to revert. It is not that "the unit is 'u' and is just not mentioned". The unit mathematically and formally disappears because the measured mass (an m so has unit u!) is devided by the purpously defined mass, the ¹²C mass (also unit u!). The devision cancelles both units, that is how it becomes dimensionless.

Sure this should be described much much better in the article and in the lede, as Lambiam initiated. Even before the "mix of isotopes" part. I myself could not create it, but others including Lambiam might give it a go. Have a nice edit. -DePiep (talk) 19:57, 26 October 2020 (UTC)

I've given it a try, also doing some shuffling of sentences and other copy editing.  --Lambiam 21:05, 26 October 2020 (UTC)

Go ahead! I am trying to explain the difficulty, here. Obviously, I could not write it myself so improvements are needed :-) -DePiep (talk) 21:55, 26 October 2020 (UTC)

The table of atomic weights in the "List of atomic weights" section leaves the atomic weight values for ₄₃Tc, ₆₁Pm, ₈₄Po–₈₉Ac, and ₉₃Np–₁₁₈Og blank. However, IUPAC tables (excluding the table on the CIAAW website) show the mass number of the most stable isotope in brackets, such as the one available at https://iupac.qmul.ac.uk/AtWt/.

I propose that the table should be changed to include the most stable nuclide, like [97] for ₄₃Tc, [222] for ₈₆Rn, [237] for ₉₃Np, etc. FrierMAnaro (talk) 09:09, 14 March 2026 (UTC)