90
Th
232.04
Thorium (Th)
Element 90 · Period 7 · Actinide series
actinide
solid at room temp
f-block
radioactive
About Thorium
Potentially safer nuclear fuel than uranium. Long half-life of 14 billion years.
Physical Properties
Atomic Mass
232.04 u
State at 25°C
Solid
Melting Point
1750 °C
Boiling Point
4820 °C
Density
11.72 g/cm³
Magnetism
Paramagnetic
Atomic Properties
Electron Configuration
[Rn] 6d² 7s²
Electron Shells
2, 8, 18, 32, 18, 10, 2
Electronegativity
1.3
Atomic Radius
237 pm
Ionization Energy
587 kJ/mol
Oxidation States
+4
Discovery & History
Discovered By
Jöns Jacob Berzelius
Discovery Year
1828
Named By
Jöns Jacob Berzelius
Name origin: Norse god Thor
Frequently Asked Questions
- Is Thorium a metal, nonmetal, or metalloid?
- Thorium is classified as a actinide.
- What state is Thorium in at room temperature?
- Thorium is a solid at standard room temperature (25°C).
- What is the atomic mass of Thorium?
- Thorium has an atomic mass of 232.04 atomic mass units (u).
- Who discovered Thorium?
- Thorium was discovered by Jöns Jacob Berzelius in 1828.
- Where is Thorium on the periodic table?
- Thorium is element number 90, located in period 7, part of the actinide series shown below the main table.