Periodic table / Alkaline earth metals
12Magnesium
Magnesium is an alkaline earth metal in group 2, period 3. At 25 °C it is a solid.
- Symbol
- Mg
- Atomic number
- 12 protons in the nucleus
- Standard atomic weight
- 24.305 ± 0.002
- Electron configuration
- [Ne] 3s2
- Electrons in each shell
- 2, 8, 2
- Group, period, block
- 2, 3, s
- Family
- Alkaline earth metals
- State at 25 °C
- solid
- Electronegativity
- 1.31 (Pauling scale)
- First ionisation energy
- 737.7 kJ/mol (7.646236 eV)
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Where these numbers come from
Atomic weight: IUPAC CIAAW, abridged standard atomic weights 2024. Electron configuration and ionisation energy: NIST Atomic Spectra Database. Family, state and electronegativity: PubChem. See Sources. Melting points, boiling points and densities are left out for now: published values differ between sources, and we will add them once each has been checked.