Astatine

Fluorine, chlorine, bromine, iodine and astatine are halogens.

Astatine was first made at Berkeley by bombarding bismuth with alpha particles, which produced astatine and released two neutrons.

Astatine, for instance, is practically unstudied. It has a name and a place on the periodic table (next to Marie Curie's polonium), but almost nothing else.