Potassium Electron Configuration
Potassium (K) · 19 electrons · Alkali metal
1s2 2s2 2p6 3s2 3p6 4s1
Noble gas notation: [Ar] 4s1
Orbital diagram
↑↓
1s↑↓
2s↑↓↑↓↑↓
2p↑↓
3s↑↓↑↓↑↓
3p↑
4s- Valence electrons
- 1
- Unpaired electrons
- 1
- Block
- s-block
- Magnetism (atom)
- paramagnetic
Electrons per shell
| K (n = 1) | 2 |
|---|---|
| L (n = 2) | 8 |
| M (n = 3) | 8 |
| N (n = 4) | 1 |
Potassium ion configurations
| Ion | Electrons | Configuration |
|---|---|---|
| K+ | 18 | [Ne] 3s2 3p6 |
How to write it
Place 19 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. Potassium sits in period 4, group 1, in the s-block, so its last electron enters an s subshell. Replacing the inner electrons with the previous noble gas gives the shorthand [Ar] 4s1.
Try potassium and its ions in the calculator, or see the full potassium data sheet.
Potassium electron configuration FAQ
What is the electron configuration of potassium?
1s² 2s² 2p⁶ 3s² 3p⁶ 4s¹. Shorthand (noble gas) notation: [Ar] 4s¹.
What is the noble gas configuration of potassium?
[Ar] 4s¹. The bracket stands for the Ar core electrons.
How many valence electrons does potassium have?
1 (outer shell (n = 4)).
How many unpaired electrons does potassium have?
1 in the ground state, following Hund’s rule. An atom with unpaired electrons is paramagnetic.
What is the electron configuration of K+?
[Ne] 3s² 3p⁶ (18 electrons).