Lutetium

Atomic symbol: Lu
Atomic number: 71
Atomic mass: 174.97

Appearance: Silvery white metal at 25°C

Group: 3
Period: 6
Series: Lanthanides
Block: d
Electron configuration: 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 5s² 5p⁶ 4f¹⁴ 5d¹ 6s²

The hardest, densest, and most expensive lanthanide metal.

Fun Fact! While lutetium is considered one of the least abundant rare Earth metals, it is still more common than gold or silver.