Support. We had this from 2002 to 2010, before any of the currently active editors changed anything, and it seemed fairly uncontroversial then. ACS and LANL are definitely reputable sources, and since IUPAC has not given such a colouring scheme, I think we can use them as the closest thing to a standard. I recognise that there are some cases (strongly radioactive elements and group 12) in which one may be able to argue from primary sources that another categorisation scheme is better; but these issues seem to be too high-level to really worry about, especially since sometimes the literature is itself undecided. I also recognise that the heaviest elements haven't been chemically characterised, but if ACS and LANL don't worry about it, then probably neither should we. This proposal seems good enough for the basic level we're writing for, and we can of course use something else when the context makes that more appropriate. The endless discussions on WT:ELEM for the last few years seem to result in changes every few years, suggesting that one cannot significantly better it, and that in this case perfect will be the enemy of good.
(Regarding the only differences: "other nonmetals" instead of "nonmetals" because noble gases are usually also considered nonmetals; LANL and ACS differ about "post-transition metals" vs "other metals" respectively, but since the former raises questions about aluminium I think it's not worth it; in 2010 WP tennessine was uncoloured because its discovery had not yet been publicly announced.)
