Terbium (Tb)

Terbium is a chemical element with symbol Tb and atomic number 65. It is a silvery-white, rare earth metal that is malleable, ductile, and soft enough to be cut with a knife.

Atomic Number

65

Atomic Mass

158.93 u

Category

lanthanide

Phase

solid

Density

8.23 g/cm³

Electron Shells

2, 8, 18, 27, 8, 2

Atomic Structure

Protons: 65 • Electrons: 65 • Neutrons: Varies by isotope

Electron Configuration: 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰ 5p⁶ 6s² 4f⁹

Discovery

1843 • Carl Gustaf Mosander