90 Th 232.038
Thorium
actinide
Properties
- Atomic number
- 90
- Atomic mass
- 232.038 u
- Category
- actinide
- Group
- f-block
- Period
- 7
- Block
- f-block
- State (room temp)
- Solid
- Outer-shell electrons
- 2
- Electronegativity
- 1.3 (Pauling)
- Density
- 11.724 g/cm³
- Melting point
- 1749.85 °C
- Boiling point
- 4787.85 °C
Electron configuration
1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰ 5p⁶ 6s² 4f¹⁴ 5d¹⁰ 6p⁶ 7s² 6d²
Noble-gas shorthand: [Rn] 6d² 7s²
Electrons per shell: 2, 8, 18, 32, 18, 10, 2 — that's 2 in the outermost shell.
About Thorium
Thorium is a chemical element with symbol Th and atomic number 90. A radioactive actinide metal, thorium is one of only two significantly radioactive elements that still occur naturally in large quantities as a primordial element (the other being uranium). It was discovered in 1828 by the Norwegian Reverend and amateur mineralogist Morten Thrane Esmark and identified by the Swedish chemist Jöns Jakob Berzelius, who named it after Thor, the Norse god of thunder.
- Discovered by Jöns Jakob Berzelius
- Appearance: silvery, often with black tarnish
Position in the periodic table
Data compiled from Wikipedia, PubChem, and IUPAC. Source.