Promethium
Atomic symbol: Pm
Atomic number: 61
Atomic mass: 145
Appearance: Silver gray solid at 25°C
Group: N/a
Period: 6
Series: Lanthanides
Block: f
Electron configuration: 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 5s² 5p⁶ 4f⁵ 6s²
Extremely radioactive.
Fun Facts! Promethium salts glow blue/ green in the dark due to its radioactivity!
The last rare Earth lanthanide metal to be discovered, Promethium was only accepted as an official element in 1949, after it was finally isolated by scientists at Oak Ridge, Tennessee in 1945!