57
La
138.91
Lanthanum (La)
Element 57 · Period 6 · Lanthanide series
lanthanide
solid at room temp
f-block
About Lanthanum
First lanthanoid. Used in camera lenses, hybrid car batteries, and catalysts.
Physical Properties
Atomic Mass
138.91 u
State at 25°C
Solid
Melting Point
920 °C
Boiling Point
3464 °C
Density
6.145 g/cm³
Magnetism
Paramagnetic
Atomic Properties
Electron Configuration
[Xe] 5d¹ 6s²
Electron Shells
2, 8, 18, 18, 9, 2
Electronegativity
1.1
Atomic Radius
240 pm
Ionization Energy
538 kJ/mol
Oxidation States
+3
Discovery & History
Discovered By
Carl Gustaf Mosander
Discovery Year
1839
Named By
Carl Gustaf Mosander
Name origin: Greek: lanthanein (to lie hidden)
Frequently Asked Questions
- Is Lanthanum a metal, nonmetal, or metalloid?
- Lanthanum is classified as a lanthanide.
- What state is Lanthanum in at room temperature?
- Lanthanum is a solid at standard room temperature (25°C).
- What is the atomic mass of Lanthanum?
- Lanthanum has an atomic mass of 138.91 atomic mass units (u).
- Who discovered Lanthanum?
- Lanthanum was discovered by Carl Gustaf Mosander in 1839.
- Where is Lanthanum on the periodic table?
- Lanthanum is element number 57, located in period 6, part of the lanthanide series shown below the main table.