57Solid
La 138.905 Atomic mass · uLanthanides
Lanthanum
Lanthanum is a soft, ductile, silvery-white metallic chemical element with symbol La and atomic number 57. It tarnishes rapidly when exposed to air and is soft enough to be cut with a knife. It gave its name to the lanthanide series, a group of 15 similar elements between lanthanum and lutetium in the periodic table:it is also sometimes considered the first element of the 6th-period transition metals.
Discovery 1839 (Carl Gustaf Mosander)
K2L8M18N18O9P2
Physical properties
Values for the element in its standard state.
- Density
- 6.146g/cm³
- Melting point
- 1,193K
- Boiling point
- 3,737K
- Atomic radius
- 169pm
- Bonding type
- Metallic
- Molar heat
- 27.11J/(mol·K)
Inside the atom
Electron arrangement and the energy behind its behavior.
Full electron configuration
1s, 2 electrons; 2s, 2 electrons; 2p, 6 electrons; 3s, 2 electrons; 3p, 6 electrons; 3d, 10 electrons; 4s, 2 electrons; 4p, 6 electrons; 4d, 10 electrons; 5s, 2 electrons; 5p, 6 electrons; 5d, 1 electrons; 6s, 2 electrons;
[Xe] represents 54 core electrons. The full view shows them explicitly.
57 electrons Orbital order preserved from source
- Electronegativity
- 1.1Pauling scale
- First ionization energy
- 538kJ/mol
- Electron affinity
- 48kJ/mol
- Van der Waals radius
- Not available
La LanthanumAtomic number 57
538kJ/mol
Atomic numberGaps indicate unavailable data
About lanthanum
- Appearance
- Silvery white
- Discovery
- 1839 (Carl Gustaf Mosander)
- Data source
- Read the reference
A missing value means it is unavailable in this reference dataset. Values can vary with measurement method and conditions.