Astronomy
·Chemical element
Thorium
Thorium (Th) is a chemical element belonging to the Actinide series (inner transition metal), with atomic number 90 and atomic mass 232.0380 u.
Stays within its layer
Astronomy
Neighbourhood in the graph
Above, what contains it; below, what it contains; on the right, what links it to another layer.
Astronomy · Chemical element
Thorium
EL2I
Identity
- Name: Thorium
- Symbol: Th
- Atomic number: 90
- Atomic mass: 232.0380 u
Position in the periodic table
- Series: Actinide
- Period: 7
- Block: f
Physico-chemical properties
- Standard state: Solid
- Melting point: 1750°C
- Density: 11.7 g/cm³
- Electron configuration: [Rn] 6d² 7s²
Scientific description
Thorium belongs to the actinide series, is naturally radioactive, and has a standard atomic mass of 232.0380 u.