89 Ac 227
Actinium
actinide
Properties
- Atomic number
- 89
- Atomic mass
- 227 u
- Category
- actinide
- Group
- f-block
- Period
- 7
- Block
- f-block
- State (room temp)
- Solid
- Outer-shell electrons
- 2
- Electronegativity
- 1.1 (Pauling)
- Density
- 10 g/cm³
- Melting point
- 1226.85 °C
- Boiling point
- 3226.85 °C
Electron configuration
1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰ 5p⁶ 6s² 4f¹⁴ 5d¹⁰ 6p⁶ 7s² 6d¹
Noble-gas shorthand: [Rn] 6d¹ 7s²
Electrons per shell: 2, 8, 18, 32, 18, 9, 2 — that's 2 in the outermost shell.
About Actinium
Actinium is a radioactive chemical element with symbol Ac (not to be confused with the abbreviation for an acetyl group) and atomic number 89, which was discovered in 1899. It was the first non-primordial radioactive element to be isolated. Polonium, radium and radon were observed before actinium, but they were not isolated until 1902.
- Discovered by Friedrich Oskar Giesel
Position in the periodic table
Data compiled from Wikipedia, PubChem, and IUPAC. Source.