Full configuration
1s² 2s² 2p⁶ 3s² 3p⁶ 3d⁸ 4s²
In the short form, [Ar] stands for the 18 electrons of argon, the noble gas before nickel. Only the electrons after it are written out.
Orbital diagram
Outer subshells only. Each box is an orbital; electrons fill singly first (Hund's rule), then pair up with opposite spins.
What the configuration tells you
Nickel is in group 10, period 4, in the d-block. It has 2 unpaired electrons in the ground state, so the atom is paramagnetic.
Configuration of nickel ions
| Ion | Configuration | Unpaired | Moment (BM) |
|---|---|---|---|
| Ni²⁺ | [Ar] 3d⁸ | 2 | 2.83 |
Moment is the spin-only magnetic moment μ = √(n(n + 2)) Bohr magnetons, where n is the number of unpaired electrons. Positive ions lose electrons from the outermost shell first, so transition metals lose their 4s or 5s electrons before d.
Nearby elements
| Z | Element | Configuration |
|---|---|---|
| 25 | Manganese | [Ar] 3d⁵ 4s² |
| 26 | Iron | [Ar] 3d⁶ 4s² |
| 27 | Cobalt | [Ar] 3d⁷ 4s² |
| 29 | Copper | [Ar] 3d¹⁰ 4s¹ |
| 30 | Zinc | [Ar] 3d¹⁰ 4s² |
| 31 | Gallium | [Ar] 3d¹⁰ 4s² 4p¹ |
Questions students ask
What is the electronic configuration of nickel?
[Ar] 3d⁸ 4s², or in full, 1s² 2s² 2p⁶ 3s² 3p⁶ 3d⁸ 4s². Nickel has atomic number 28.
How many electrons are in each shell of nickel?
2, 8, 16, 2 (K, L, M, N… shells in order).
How many unpaired electrons does nickel have?
2 in the ground state, so nickel atoms are paramagnetic.
What is the electronic configuration of Ni²⁺?
[Ar] 3d⁸, with 2 unpaired electrons.