Atomic Element Z = 57 • Lanthanide
Lanthanum (La) — Atomic Data, Electron Shells & Reactions
Lanthanum (symbol La, atomic number 57) has a standard atomic weight of 138.91 u and ground-state configuration [Xe] 5d1 6s2.
Atomic Number (Z)
57
IUPAC Symbol
La
Standard Atomic Weight
138.91 g/mol
Period / Group / Block
6 / f-block / f-block
Condensed Electron Config
[Xe] 5d1 6s2
Full Subshell Config
1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 5s2 5p6 5d1 6s2
Principal Shell Occupancy
[2, 8, 18, 18, 9, 2]
Pauling Electronegativity
1.1
First Ionization Energy
538 kJ/mol
Covalent Radius
207 pm
Melting Point
1193 K (919.85 °C)
Boiling Point
3737 K (3463.85 °C)
Density
6.145 g/cm³
Oxidation States
+3
La (Z=57) — Valence shell highlighted in vermilion