61 Pm 145
Promethium
lanthanide
Properties
- Atomic number
- 61
- Atomic mass
- 145 u
- Category
- lanthanide
- Group
- f-block
- Period
- 6
- Block
- f-block
- State (room temp)
- Solid
- Outer-shell electrons
- 2
- Electronegativity
- 1.13 (Pauling)
- Density
- 7.26 g/cm³
- Melting point
- 1041.85 °C
- Boiling point
- 2999.85 °C
Electron configuration
1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰ 5p⁶ 6s² 4f⁵
Noble-gas shorthand: [Xe] 4f⁵ 6s²
Electrons per shell: 2, 8, 18, 23, 8, 2 — that's 2 in the outermost shell.
About Promethium
Promethium, originally prometheum, is a chemical element with the symbol Pm and atomic number 61. All of its isotopes are radioactive; it is one of only two such elements that are followed in the periodic table by elements with stable forms, a distinction shared with technetium. Chemically, promethium is a lanthanide, which forms salts when combined with other elements.
- Discovered by Chien Shiung Wu
- Named by Isotopes of promethium
- Appearance: metallic
Position in the periodic table
Data compiled from Wikipedia, PubChem, and IUPAC. Source.