Terbium
A rare earth used in green phosphors and solid-state devices.
Inside the Terbium atom
Switch between Bohr and Quantum Cloud modes to compare a simple teaching model with a more realistic probability-based view, and follow the guided tour to explore the Terbium atom step by step.
Electron configuration
[Xe] 4f9 6s2
A neutral Terbium atom has 65 electrons (equal to its proton count). Choosing a different isotope above changes only the neutron count.
Shell distribution
Electrons fill inner shells before outer ones; the outermost (valence) shell drives the element's chemistry.
Physical & atomic properties
- State (room temp)
- Solid
- Melting point
- 1629 K (1356 °C)
- Boiling point
- 3503 K (3230 °C)
- Density
- 8.229 g/cm³
- Electronegativity
- 1.2 Pauling
- Atomic radius
- 175 pm
- 1st ionization energy
- 566 kJ/mol
- Category
- Lanthanides
Discovery & naming
- Discovered
- 1843
- Discovered by
- Carl Gustaf Mosander
- Origin of name
- Ytterby, a village in Sweden.
Notable uses
Green phosphors in displays and magnetostrictive alloys.
Where Terbium comes from
Neutron star mergers
An r-process element: built by rapid neutron capture, not by ordinary stellar burning.
Simplified origin map — many elements form through more than one astrophysical pathway.
Summary
- Atomic number
- 65
- Atomic mass
- 158.93
- Category
- Lanthanides
- Group · Period
- — · 6
- Block
- f-block
- Shells
- 2 · 8 · 18 · 27 · 8 · 2