La
Lanthanum
Atomic number: 57Mass: 138.905 uCategory: Lanthanide
About Lanthanum
Lanthanum is a soft, ductile, silvery-white metal that tarnishes rapidly when exposed to air. It is the first element in the lanthanide series. It is used in camera and telescope lenses to produce a special glass that reduces chromatic aberration.
Properties
Period
6
Group
N/A
Block
F
Category
Lanthanide
Electronegativity
1.10 (Pauling)
Ionization Energy
538.1 kJ/mol
Melting Point
1193 K (920°C)
Boiling Point
3737 K (3464°C)
Density
6.162 g/cm³
Oxidation States
+3
Electron Configuration
1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 5s² 5p⁶ 5d¹ 6s²
[Xe] 5d¹ 6s²
Shell 1:2e⁻
Shell 2:8e⁻
Shell 3:18e⁻
Shell 4:18e⁻
Shell 5:9e⁻
Shell 6:2e⁻
Real-World Uses
Camera lenses
Hybrid car batteries
Catalytic cracking
Lighter flints
Telescope mirrors
Fun Fact
High-end camera lenses often contain lanthanum oxide to improve optical clarity — your photos may have been taken through lanthanum!