Atomic number 90
Thorium
Actinide
Quick facts
- Atomic mass
- 232.04
- Group
- —
- Period
- 7
- State (STP)
- solid
- Electronegativity
- 1.30
- Common ox. states
- +4
Properties
Electron configuration
[Rn] 6d² 7s²
- Ionization energy
- 587.0 kJ/mol
- Electron affinity
- —
- Melting point
- 2023.00 K (1749.8 °C)
- Boiling point
- 5061.00 K (4787.9 °C)
How it bonds· family overview
Thorium (Th) is an actinide. Like the lanthanides it tends toward a +3 oxidation state, but the early actinides (Th–Am) routinely access +4, +5, +6, even +7 because the 5f electrons are easier to ionize. Most actinides are radioactive; their "bonding" in school is read off the periodic table, not measured in lab.