Element 71 · Lanthanide
Lutetium (Lu) — Element 71
Latin Lutetia — Paris
Lutetium (Lu) is a lanthanide in Period 6 (f-block) of the periodic table with atomic number 71, standard atomic weight 174.97 u, and ground-state electron configuration [Xe] 4f¹⁴ 5d¹ 6s². At standard temperature and pressure it is classified as a solid with 3 valence electrons and common oxidation states +3.
PET scan detectors, catalysts
What are the atomic properties and physical constants of Lutetium?
Reference constants compiled from IUPAC standard atomic weights, the NIST Atomic Spectra Database, and the CRC Handbook.
- Atomic number (Z)
- 71
- Standard atomic mass
- 174.97 u
- Chemical family
- Lanthanide
- Ground-state configuration
- [Xe] 4f¹⁴ 5d¹ 6s²
- Electrons per shell
- 2, 8, 18, 32, 9, 2
- Valence electrons
- 3
- Common ion charges / oxidation states
- +3
- Phase at STP
- Solid
- Pauling electronegativity
- 1.27 Pauling
- First ionization energy
- 524 kJ/mol
- Atomic radius
- 217 pm
- Melting point
- 1,652 °C
- Boiling point
- 3,402 °C
- Discovery year
- 1907
- Table coordinate
- Period 6, f-block
- Radioactivity
- Has stable isotope(s)
How are electrons arranged across Lutetium’s shells?
A neutral Lutetium atom contains 71 electrons distributed across 6 occupied principal energy shells ([Xe] 4f¹⁴ 5d¹ 6s²). The table below compares Lutetium’s shell occupancy against each shell’s theoretical 2n² capacity.
| Principal Shell (n) | Spectroscopic Letter | Electrons in Lu | Max Shell Capacity (2n²) |
|---|---|---|---|
| n = 1 | K | 2 e⁻ | 2 e⁻ |
| n = 2 | L | 8 e⁻ | 8 e⁻ |
| n = 3 | M | 18 e⁻ | 18 e⁻ |
| n = 4 | N | 32 e⁻ | 32 e⁻ |
| n = 5 | O | 9 e⁻ | 50 e⁻ |
| n = 6 | P | 2 e⁻ | 72 e⁻ |
Frequently Asked Questions about Lutetium (Lu)
What is the atomic mass and atomic number of Lutetium (Lu)?
Lutetium (Lu) has atomic number Z = 71 (71 protons in its nucleus) and an IUPAC standard atomic weight of 174.97 u. It sits in Period 6 in the f-block and is classified as a lanthanide.
What is the ground-state electron configuration of Lutetium?
The neutral ground-state electron configuration of Lutetium (Z = 71) is [Xe] 4f¹⁴ 5d¹ 6s². Across its 6 occupied principal shells (n = 1 to n = 6), the electrons per shell are 2, 8, 18, 32, 9, 2, with 3 valence electrons participating in bonding.
What are the common ion charges and electronegativity of Lutetium?
Lutetium commonly forms +3 oxidation states or ion charges in compounds. Its Pauling electronegativity is 1.27 and its first ionization energy is 524 kJ/mol.
When was Lutetium discovered and what is it used for?
Lutetium was discovered in 1907 (Latin Lutetia — Paris). PET scan detectors, catalysts
How does Lutetium compare to neighboring elements?
Other lanthanide elements: