Boron Electron Configuration
Boron (B) · 5 electrons · Metalloid
1s2 2s2 2p1
Noble gas notation: [He] 2s2 2p1
Orbital diagram
↑↓
1s↑↓
2s↑
2p- Valence electrons
- 3
- Unpaired electrons
- 1
- Block
- p-block
- Magnetism (atom)
- paramagnetic
Electrons per shell
| K (n = 1) | 2 |
|---|---|
| L (n = 2) | 3 |
Boron ion configurations
| Ion | Electrons | Configuration |
|---|---|---|
| B3+ | 2 | 1s2 |
How to write it
Place 5 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. Boron sits in period 2, group 13, in the p-block, so its last electron enters a p subshell. Replacing the inner electrons with the previous noble gas gives the shorthand [He] 2s2 2p1.
Try boron and its ions in the calculator, or see the full boron data sheet.
Boron electron configuration FAQ
What is the electron configuration of boron?
1s² 2s² 2p¹. Shorthand (noble gas) notation: [He] 2s² 2p¹.
What is the noble gas configuration of boron?
[He] 2s² 2p¹. The bracket stands for the He core electrons.
How many valence electrons does boron have?
3 (outer shell (n = 2)).
How many unpaired electrons does boron have?
1 in the ground state, following Hund’s rule. An atom with unpaired electrons is paramagnetic.
What is the electron configuration of B3+?
1s² (2 electrons).