57
138.91 u
La
Lanthanum
Lanthanide
Atomic Structure
Physical State
Group
3
Period
6
Block
d
Electron Configuration
[Xe] 5d¹ 6s²
Physical Properties
Atomic Mass:
138.91 u
Electronegativity:
1.1
Atomic Radius:
270 pm
Ionization Energy:
5.577 eV
Density:
6.16 g/cm³
Melting Point:
1193 K
Boiling Point:
3737 K
Historical Information
Discovered By:
Carl Gustaf Mosander
Year Discovered:
1839