University of Kentucky chemistry professors John P. Selegue and F. James Holler are collecting comic book references to chemical elements. On their Periodic Table of Comic Books site, you can click through the standard periodic table to see pages from comic books that mention specific elements. The samples seem to be weighted pretty heavily to classic, Golden and Silver Age stuff — there's a lot of 1940s Wonder Woman and miscellaneous anthology series from the 1960s.
They don't have all the elements accounted for yet. In particular, the lanthanides and actinides — aka, those two rows at the bottom where everything ends in "ium" — are lacking comic book shout-outs. Maybe you can help!
Thanks to Jennifer Ouellette!