61 Pm Promethium [145]
Lanthanide
Promethium 钷
[Xe] 4f⁵ 6s²
- Period 6
- Group —
- Block f
- Solid
Electron configuration
1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 4f⁵ 5s² 5p⁶ 6s²
Orbital diagram (valence)
- Electrons per shell
- 2, 8, 18, 23, 8, 2
- Unpaired electrons
- 5
- Zeff (Slater)
- 2.85
Properties
- Atomic weight
- [145]
- Electronegativity (Pauling)
- no data
- First ionization energy
- 535.5 kJ/mol
- Electron affinity
- no data
- Covalent radius
- 199 pm
- van der Waals radius
- 236 pm
- Melting point
- 1315 K
- Boiling point
- 3273 K
- Density
- 7.26 g/cm³
- Melting / boiling point
- 1041.8 °C / 2999.8 °C
- Common oxidation states
- +3
- Discovered
- 1945
Brackets give the mass number of the longest-lived isotope
Periodic trend
Data: PubChem periodic table (public domain); atomic weights are IUPAC abridged standard values; covalent radii from Cordero et al. (2008).