For inquiring minds, the type face that closely approximates the style featured bright and bold on academic posters of the periodic table is the Univers family (not in the standard quiver of fonts but downloaded for free here). Of course, there’s no universal standards for the heraldry of such a chart, but such achieving such a look, with a little nostalgia for the high school science classroom and cleanly monolithic, I think is a fitting way to display the octaves of the Elements—sort of like musical notation itself. The strangeness of particles that underlies the noble appearance of the Atom have so far defied such an immediate and tidy composition, like being ordered according to periods whose gaps were realized, filled in, and known before the missing elements were even discovered. A framework of theories were affirmed, stepwise, with the zoo of subatomic entities and mannerisms that were also predicted and discovered one by one—suggesting that something a bit unwieldy may yet also be described or describable in human understanding. Maybe the whole range of fonts and type-setting displays a certain periodicity as well but there is always space for variation and to wedge style between style.
