Lutetium (Lu)
Element 71 · lanthanide · group 3, period 6
Lutetium is element 71, a lanthanide in group 3 and period 6. Its electron configuration is [Xe] 4f14 5d1 6s2. The shells fill 2, 8, 18, 32, 9, 2. The f-block elements draw on three subshells, so a single valence count is not meaningful for them. It commonly forms ions with a charge of +3.
- 71 protons
- 2/3 valence e−
- +3
- f-block
Properties
| Atomic number | 71 |
|---|---|
| Symbol | Lu |
| Standard atomic weight | 174.97 u |
| Group | 3 |
| Period | 6 |
| Block | f-block |
| Category | lanthanide |
| Electron configuration | 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 4f14 5s2 5p6 5d1 6s2 |
| Noble-gas notation | [Xe] 4f14 5d1 6s2 |
| Electrons per shell | 2, 8, 18, 32, 9, 2 |
| Valence electrons | 2 or 3 |
| Common ionic charge | +3 |
| Electronegativity (Pauling) | 1.27 |
| Protons / electrons | 71 / 71 |
Electron configuration of lutetium
Orbitals fill from the lowest energy upward. Writing that out for lutetium gives 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 4f14 5s2 5p6 5d1 6s2, which is 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 4f14 5s2 5p6 5d1 6s2 in plain text.
Everything up to Xe is the same as in that noble gas, so it is usually abbreviated to [Xe] 4f14 5d1 6s2. The part outside the bracket is what does the chemistry.
| Subshell | Electrons | Capacity |
|---|---|---|
| 1s | 2 | 2 |
| 2s | 2 | 2 |
| 2p | 6 | 6 |
| 3s | 2 | 2 |
| 3p | 6 | 6 |
| 3d | 10 | 10 |
| 4s | 2 | 2 |
| 4p | 6 | 6 |
| 4d | 10 | 10 |
| 4f | 14 | 14 |
| 5s | 2 | 2 |
| 5p | 6 | 6 |
| 5d | 1 | 10 |
| 6s | 2 | 2 |
Lutetium ion charge
Lutetium commonly forms ions with a charge of +3.
Common questions
How many valence electrons does lutetium have?
There is no single agreed answer for lutetium. The f-block elements draw on three subshells, so a single valence count is not meaningful for them. Check which convention your course uses before answering.
What is the electron configuration of lutetium?
1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 4f14 5s2 5p6 5d1 6s2, or [Xe] 4f14 5d1 6s2 written from the previous noble gas. Orbitals fill lowest energy first.
What is the charge of lutetium?
Lutetium commonly forms ions with a charge of +3. Transition metals have several accessible oxidation states, which is why more than one charge is listed.
How many protons, electrons and neutrons does lutetium have?
A neutral lutetium atom has 71 protons and 71 electrons. Its standard atomic weight is 174.97, so the most common isotope has about 104 neutrons.
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