Lutetium (Lu) – element 71
Lutetium is a chemical element with the symbol Lu and atomic number 71. It is a lanthanide in group 3 (lanthanides), period 6 of the periodic table (d-block), and is a solid at room temperature.
Lutetium (Lu) has atomic number 71, atomic mass 174.97 u and electron configuration [Xe] 4f14 5d1 6s2.
Lutetium facts
| Symbol | Lu |
|---|---|
| Atomic number | 71 |
| Atomic mass | 174.97 u (g/mol) |
| Category | lanthanide |
| Group | group 3 (lanthanides) |
| Period | 6 |
| Block | d-block |
| Phase at 20 °C | Solid |
| Electron configuration | 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s2 4f14 5d1 |
| Noble-gas notation | [Xe] 4f14 5d1 6s2 |
| Electrons per shell | 2, 8, 18, 32, 9, 2 |
Bohr model and shells
Lutetium has 71 electrons in 6 shells: 2, 8, 18, 32, 9, 2. Full configuration and noble-gas notation are in the table; work out any element or ion with the electron configuration calculator.
Physical and atomic properties
| Melting point | 1925 K (1651.8 °C) |
|---|---|
| Boiling point | 3675 K (3401.8 °C) |
| Density | 9.841 g/cm³ |
| Electronegativity (Pauling) | 1.27 |
| Electron affinity | 33.4 kJ/mol |
| Ionization energies | 523.5, 1340, 2022.3 kJ/mol (1st, 2nd, 3rd) |
| Molar heat capacity | 26.86 J/(mol·K) |
| Discovered by | Georges Urbain |
Use the atomic mass in the molar mass calculator for any formula containing Lu.
Position in the periodic table
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Frequently asked questions
What is the atomic mass of lutetium?
The atomic mass of lutetium is 174.97 u, so one mole of lutetium atoms weighs 174.97 g.
What is the electron configuration of lutetium?
Lutetium has 71 electrons: 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰ 5p⁶ 6s² 4f¹⁴ 5d¹, or [Xe] 4f¹⁴ 5d¹ 6s² in noble-gas notation. Electrons per shell: 2, 8, 18, 32, 9, 2.
Is lutetium a metal?
Yes. Lutetium is a lanthanide.
Where is lutetium on the periodic table?
Lutetium is in group 3 (lanthanides), period 6, in the d-block.
Data: Periodic-Table-JSON (CC BY-SA 3.0); standard atomic weights from IUPAC (abridged). Values in brackets are the mass number of the longest-lived isotope.