Periodic Table
12
Mg
24.305
Magnesium
Alkaline EarthBurns with brilliant white light; central atom of chlorophyll.
Electronic Configuration
[Ne] 3s²or1s² 2s² 2p⁶ 3s²
Electron shells
2e⁻n=1
8e⁻n=2
2e⁻n=3
Properties
Atomic number
12
Atomic mass
24.305 u
Category
Alkaline Earth
Block / Group / Period
s · 2 · 3
Valence electrons
2
Oxidation states
+2
Electronegativity
1.31
Atomic radius
145 pm
Ionization energy
738 kJ/mol
Electron affinity
0 kJ/mol
Melting point
923 K / 650 °C
Boiling point
1363 K / 1090 °C
Density
1.738 g/cm³
State at 25 °C
solid
JEE / NEET notes
- Diagonal relationship with Li.
- Burns in CO₂ and N₂ (forms MgO + C, and Mg₃N₂).
- Grignard reagent RMgX — versatile in organic synthesis.
Flame test
Brilliant white (no characteristic colour, high energy)
Ores & extraction
Ores: Magnesite (MgCO₃), Dolomite (CaCO₃·MgCO₃), Carnallite
Uses
Lightweight alloys · Flares & fireworks · Grignard reagents · Antacids
Important compounds
MgOMgSO₄·7H₂O (Epsom salt)Mg(OH)₂Mg₃N₂
Personal Notes
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