The "Atomic Era" was barely five years old when PopSci published this article on the new neptunium family of radioactive elements. Already, "atomic-age discoveries... have been happening too fast for the chemistry and physics books to keep up." The quest to fill the empty slots of the periodic table became an obsession after scientists grasped the awe-inspiring potential of nuclear energy.
In 1950, there were 96 known chemical elements (today we have 118.) The U.S. Atomic Energy Commission had just de-classified four charts of the radioactive families of elements, which PopSci painstakingly reproduced as a permanent reference for readers. Up for debate was whether the unstable, lab-made elements were just as legit as their naturally occurring counterparts. "With former distinctions between 'natural' and 'artificial' rapidly vanishing in modern science, the answer seems to be yes."
Read the full story in New Atomic Charts Reveal Secrets of Radio-Elements