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, which is 2 in the outermost shell.
Related: electron configuration, the Bohr model, valence electrons.
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
Thorium: frequently asked questions
- What is Thorium?
- Thorium (Th) is the chemical element with atomic number 90. It is a metal: specifically an actinide.
- What is the atomic number of Thorium?
- Thorium's atomic number is 90, which means every Thorium atom has 90 protons in its nucleus.
- What is the electron configuration of Thorium?
- The electron configuration of Thorium is 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s2 4f14 5d10 6p6 7s2 6d2 (noble-gas shorthand: [Rn] 6d2 7s2). Its electrons are arranged in shells of 2, 8, 18, 32, 18, 10, 2, with 2 in the outermost shell.
- Is Thorium a metal or a nonmetal?
- Thorium is a metal: specifically an actinide.
- What group and period is Thorium in?
- Thorium sits in the f-block (the actinide row) of period 7 on the periodic table.
- Is Thorium a solid, liquid, or gas?
- At room temperature, Thorium is a solid.
Position in the periodic table
Data compiled from Wikipedia, PubChem, and IUPAC. Source.