Magnesium (Mg): Electron Configuration, Properties and Uses
Magnesium (Mg): Electron Configuration, Properties and Uses
Electron configuration [Ne] 3s2 · group 2 · period 3 · Ar 24.305
Magnesium data
- Atomic number
- 12
- Relative atomic mass
- 24.305
- Group
- 2
- Period
- 3
- Block
- s
- Category
- Alkaline earth metal
- Electron configuration
- [Ne] 3s2
- Full configuration
- 1s2 2s2 2p6 3s2
- Electrons per shell
- 2, 8, 2 (K L M)
- Valence electrons
- 2
- Electronegativity (Pauling)
- 1.31
- First ionisation energy
- 7.646 eV
- Atomic radius (van der Waals)
- 173 pm
- State at room temperature
- Solid
- Melting point
- 650 °C
- Boiling point
- 1090 °C
- Density
- 1.74 g/cm³
- Common oxidation states
- +2
- Discovered
- 1808
Source: PubChem (NIH, accessed 13 Nov 2026); atomic mass: IUPAC standard atomic weight.
Electron shell diagram
K 2 · L 8 · M 2
Orbital diagram (outer electrons)
About magnesium
Magnesium is a chemical element with the symbol Mg and atomic number 12. It is an alkaline earth metal in group 2, period 3, s-block. Magnesium was first discovered in 1808. Magnesium is a solid at room temperature, melting at 650 °C and boiling at 1090 °C.
Magnesium electron configuration
The electron configuration of magnesium is 1s2 2s2 2p6 3s2, or in short [Ne] 3s2. Its electrons occupy 3 shells: K = 2, L = 8, M = 2. Magnesium has 2 valence electrons in the M shell (3s2), which is why it sits in group 2. When it forms cations, electrons leave the outermost subshell first: Mg2+ = [Ne] (like neon).
Filling order: 1s2(2) → 2s2(4) → 2p6(10) → 3s2(12)
Uses of magnesium
The main uses of magnesium include lightweight alloys for vehicles and aircraft, flares and fireworks, antacids and laxatives, and Grignard reagents. For research and analysis you can browse magnesium compounds in the AMI Scientific catalogue.
Safety
Magnesium ribbon and powder burn with a very bright flame; the fire must not be put out with water. Always read the safety data sheet (SDS) before working with a chemical.
Other elements in group 2
Frequently asked questions
What is the electron configuration of magnesium?
The electron configuration of magnesium (Mg, atomic number 12) is 1s2 2s2 2p6 3s2, or [Ne] 3s2 in short. By shell: 2, 8, 2.
How many valence electrons does magnesium have?
Magnesium has 2 valence electrons.
Which group and period is magnesium in?
Magnesium is in group 2, period 3, s-block.
What is the atomic mass of magnesium?
The relative atomic mass of magnesium is 24.305. Use it to calculate molar mass with the molar mass calculator.
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