the.com/actinide
The periodic table's danger aisle: 15 elements, mostly radioactive, all overachievers.
means Any of the 15 heavy elements from actinium through lawrencium, the family that includes uranium and plutonium and most of the stuff you're warned not to touch.
from Named after actinium, the first element of the group, whose own name comes from the Greek 'aktis' or 'aktinos' meaning 'ray' or 'beam' — a nod to its radioactivity, discovered in the late 1800s. The '-ide' suffix just marks it as a family grouping, the same pattern chemists use for halides and oxides.
- lineup
- actinium through lawrencium, atomic numbers 89 to 103
- star member
- uranium, which powers reactors and ends wars
- lab-made majority
- most exist only because humans synthesized them
- shared trait
- filling the mysterious 5f electron subshell