71 Lu
Lanthanide
Lutetium
Hardest, densest lanthanide.
Properties of Lutetium
- Atomic number (Z)
- 71
- Symbol
- Lu
- Atomic mass
- 174.97 g/mol
- Category
- Lanthanide
- Group
- 3
- Period
- 6
- Electron configuration
- [Xe] 4f¹⁴ 5d¹ 6s²
- Electronegativity (Pauling)
- 1.27
- Atomic radius
- 217 pm
- First ionization energy
- 524 kJ/mol
- Melting point
- 1925 K (1651.8 °C)
- Boiling point
- 3675 K (3401.8 °C)
- Density
- 9.84 g/cm³
- Phase at 25 °C
- Solid
- Discovered
- Discovered in 1907