57 La Lanthanum 138.91
Lanthanide
Lanthanum 镧
[Xe] 5d¹ 6s²
- Period 6
- Group —
- Block f
- Solid
Electron configuration
1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 5s² 5p⁶ 5d¹ 6s²
Orbital diagram (valence)
- Electrons per shell
- 2, 8, 18, 18, 9, 2
- Unpaired electrons
- 1
- Zeff (Slater)
- 3.00
Properties
- Atomic weight
- 138.91
- Electronegativity (Pauling)
- 1.1
- First ionization energy
- 538.1 kJ/mol
- Electron affinity
- 48.24 kJ/mol
- Covalent radius
- 207 pm
- van der Waals radius
- 240 pm
- Melting point
- 1191 K
- Boiling point
- 3737 K
- Density
- 6.15 g/cm³
- Melting / boiling point
- 917.9 °C / 3463.8 °C
- Common oxidation states
- +3
- Discovered
- 1839
Lanthanum in the course
The lessons that discuss this element most (ranked by mentions).
Periodic trend
Data: PubChem periodic table (public domain); atomic weights are IUPAC abridged standard values; covalent radii from Cordero et al. (2008).