65 Tb 158.925

Terbium

lanthanide

Properties

Atomic number
65
Atomic mass
158.925 u
Category
lanthanide
Group
f-block
Period
6
Block
f-block
State (room temp)
Solid
Outer-shell electrons
2
Electronegativity
1.1 (Pauling)
Density
8.23 g/cm³
Melting point
1355.85 °C
Boiling point
3122.85 °C

Electron configuration

1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰ 5p⁶ 6s² 4f⁹

Noble-gas shorthand: [Xe] 4f⁹ 6s²

Electrons per shell: 2, 8, 18, 27, 8, 2 — that's 2 in the outermost shell.

See how electron configuration is built →

Tb
Bohr model — outer-shell electrons in blue

About Terbium

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. Terbium is never found in nature as a free element, but it is contained in many minerals, including cerite, gadolinite, monazite, xenotime and euxenite.

Position in the periodic table

Open the interactive periodic table →

Data compiled from Wikipedia, PubChem, and IUPAC. Source.