Magnesium (Mg)
[Ne] 3s². 0 unpaired electrons, period 3, group 2, s block.
Element or ion
Type a symbol, a name or an atomic number, add a charge such as Fe3+ or Cl-, or tap an element in the table. Orbitals fill from m = −l up, spin +½ first.
MgMagnesium, Z = 12, 24.305 u
[Ne] 3s2
In full: 1s² 2s² 2p⁶ 3s²
- Blocks block
- Period3
- Group2
- Valence2
- Unpaired0
- MagneticDia
Last electron 3s
- n3shell
- l0s subshell
- m0orbital
- s−½spin down
Step by step
- Magnesium has 12 electrons.
- Fill in (n + l) order: 1s² 2s² 2p⁶ 3s².
- Write the subshells in order of n: 1s² 2s² 2p⁶ 3s².
- Replace the neon core with [Ne]: [Ne] 3s².
Magnesium (Mg): the numbers
| Atomic number | 12 |
|---|---|
| Atomic mass | 24.305 u |
| Period | 3 |
| Group | 2 |
| Block | s block |
| Valence electrons | 2 |
| Unpaired electrons | 0 |
| Magnetic | diamagnetic |
| Last electron | 3s: n = 3, l = 0, m = 0, s = −1/2 |
Magnesium (Mg): quick answers
What is the electronic configuration of magnesium?
Magnesium has 12 electrons: 1s² 2s² 2p⁶ 3s², or [Ne] 3s² in short.
How many unpaired electrons does magnesium have?
Magnesium has 0 unpaired electrons, so it is diamagnetic. Put one electron in each box of a subshell before pairing (Hund’s rule) to see them.
What are the quantum numbers of the last electron of magnesium?
The last electron goes into 3s: n = 3, l = 0, m = 0, s = −1/2. Orbitals fill from m = −l up, spin +½ first.