Actinium

Atomic symbol: Ac
Atomic number: 89
Atomic mass: 227

Appearance: Silvery-white solid with a blue glow at 25°C

Group: N/a Period: 7
Series: Actinides
Block: f
Electron configuration: 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 5s² 5p⁶ 4f¹⁴ 5d¹⁰ 6s² 6p⁶ 6d¹ 7s²

Highly radioactive and glow in the dark.

Fun Fact! Actinium, polonium and radium were all discovered in the same uranium ore.