Magnesium (Mg)
Magnesium (Mg) is element 12, an alkaline earth metal. Atomic mass 24.305, configuration [Ne] 3s². Properties, isotopes, oxidation states, uses and history, with an interactive 3D atom model.
Key facts
| Atomic number | 12 |
|---|---|
| Symbol | Mg |
| Standard atomic weight | [24.304,24.307] |
| Category | Alkaline Earth Metal |
| Group | 2 |
| Period | 3 |
| State at room temperature | Solid |
| Electron configuration | [Ne] 3s² |
| Valence electrons | 2 |
| Common oxidation states | +2 |
| Common ions | Mg²⁺ |
| Electronegativity (Pauling) | 1.31 |
| First ionization energy | 738 kJ/mol |
| Atomic radius | 145 pm |
| Density | 1.74 g/cm³ |
| Melting point | 650°C |
| Boiling point | 1090°C |
| Specific heat | 1.023 J/(g·°C) |
Natural isotopes
- Mg-24: Stable (78.99%)
- Mg-25: Stable (10.00%)
- Mg-26: Stable (11.01%)
Common uses
- Aerospace alloys
- Flares/Fireworks
- Antacids
Where it matters
- Biological photosynthesis (Chlorophyll center)
- Lightweight alloys
Hazards
- Flammable (metal fire difficult to extinguish)
History
| Discovered | 1755 (Identified); 1808 (Isolated) |
|---|---|
| Discovered by | Joseph Black (Id.); Humphry Davy (Iso.) |
| Name | Derived from Magnesia district |