Cobalt Electron Configuration
Orbital diagram
- Valence electrons
- 9
- Unpaired electrons
- 3
- Block
- d-block
- Magnetism (atom)
- paramagnetic
Electrons per shell
| K (n = 1) | 2 |
|---|---|
| L (n = 2) | 8 |
| M (n = 3) | 15 |
| N (n = 4) | 2 |
Cobalt ion configurations
| Ion | Electrons | Configuration |
|---|---|---|
| Co2+ | 25 | [Ar] 3d7 |
| Co3+ | 24 | [Ar] 3d6 |
How to write it
Place 27 electrons into subshells in the Aufbau order (1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 6s, 4f, 5d, 6p, 7s, 5f, 6d, 7p), filling s with 2, p with 6, d with 10 and f with 14. Cobalt sits in period 4, group 9, in the d-block, so its last electron enters a d subshell. Replacing the inner electrons with the previous noble gas gives the shorthand [Ar] 3d7 4s2.
Try cobalt and its ions in the calculator, or see the full cobalt data sheet.
Cobalt electron configuration FAQ
What is the electron configuration of cobalt?
1s² 2s² 2p⁶ 3s² 3p⁶ 3d⁷ 4s². Shorthand (noble gas) notation: [Ar] 3d⁷ 4s².
What is the noble gas configuration of cobalt?
[Ar] 3d⁷ 4s². The bracket stands for the Ar core electrons.
How many valence electrons does cobalt have?
9 (2 outer s + 7 d electrons; 2 in the outermost shell).
How many unpaired electrons does cobalt have?
3 in the ground state, following Hund’s rule. An atom with unpaired electrons is paramagnetic.
What is the electron configuration of Co2+?
[Ar] 3d⁷ (25 electrons). Transition metal cations lose their outer s electrons before d electrons.
What is the electron configuration of Co3+?
[Ar] 3d⁶ (24 electrons). Transition metal cations lose their outer s electrons before d electrons.