Strontium Electron Configuration
Strontium (Sr) · 38 electrons · Alkaline earth metal
1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 5s2
Noble gas notation: [Kr] 5s2
Orbital diagram
↑↓
1s↑↓
2s↑↓↑↓↑↓
2p↑↓
3s↑↓↑↓↑↓
3p↑↓↑↓↑↓↑↓↑↓
3d↑↓
4s↑↓↑↓↑↓
4p↑↓
5s- Valence electrons
- 2
- Unpaired electrons
- 0
- Block
- s-block
- Magnetism (atom)
- diamagnetic
Electrons per shell
| K (n = 1) | 2 |
|---|---|
| L (n = 2) | 8 |
| M (n = 3) | 18 |
| N (n = 4) | 8 |
| O (n = 5) | 2 |
Strontium ion configurations
| Ion | Electrons | Configuration |
|---|---|---|
| Sr2+ | 36 | [Ar] 3d10 4s2 4p6 |
How to write it
Place 38 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. Strontium sits in period 5, group 2, in the s-block, so its last electron enters an s subshell. Replacing the inner electrons with the previous noble gas gives the shorthand [Kr] 5s2.
Try strontium and its ions in the calculator, or see the full strontium data sheet.
Strontium electron configuration FAQ
What is the electron configuration of strontium?
1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 5s². Shorthand (noble gas) notation: [Kr] 5s².
What is the noble gas configuration of strontium?
[Kr] 5s². The bracket stands for the Kr core electrons.
How many valence electrons does strontium have?
2 (outer shell (n = 5)).
How many unpaired electrons does strontium have?
0 in the ground state, following Hund’s rule. With all electrons paired, the atom is diamagnetic.
What is the electron configuration of Sr2+?
[Ar] 3d¹⁰ 4s² 4p⁶ (36 electrons).