1224.305MgMagnesium
Magnesium (Mg) — element 12alkaline earth metal · group 2, period 3
Magnesium is a chemical element with the symbol Mg and atomic number 12. It is an alkaline earth metal in group 2, period 3 of the periodic table (the s-block), with a standard atomic mass of 24.305 u. At room temperature (25 °C) magnesium is a solid.
💡 Known for: A light structural metal that burns with a brilliant white flame and sits at the centre of every chlorophyll molecule.
# Magnesium properties
| Symbol | Mg |
|---|---|
| Atomic number | 12 |
| Atomic mass | 24.305 u |
| Category | alkaline earth metal |
| Group | 2 |
| Period | 3 |
| Block | s-block |
| Electron configuration | [Ne] 3s² |
| Full configuration | 1s² 2s² 2p⁶ 3s² |
| Electrons per shell | 2, 8, 2 |
| Protons / electrons | 12 / 12 |
| State at 25 °C | solid |
| Melting point | 923 K (649.9 °C, 1201.7 °F) |
| Boiling point | 1363 K (1089.8 °C, 1993.7 °F) |
| Density | 1.738 g/cm³ |
| Electronegativity (Pauling) | 1.31 |
| First ionization energy | 7.646 eV |
| Atomic radius | 145 pm |
| Discovered | 1808 |
# Electron configuration of magnesium
The electron configuration of magnesium is [Ne] 3s², written out in full as 1s² 2s² 2p⁶ 3s². Its 12 electrons fill 3 shells as 2, 8, 2, so the outermost shell holds 2 electrons. As a group 2 element, magnesium has 2 valence electrons.
# Related elements
NaSodiumprevious elementAlAluminiumnext elementBeBerylliumgroup 2CaCalciumgroup 2SrStrontiumgroup 2BaBariumgroup 2RaRadiumgroup 2
# Magnesium FAQ
What is the atomic number of magnesium?
The atomic number of magnesium is 12: every magnesium atom has 12 protons in its nucleus. Its symbol is Mg.
What is the atomic mass of magnesium?
The standard atomic mass of magnesium is 24.305 u.
What is the electron configuration of magnesium?
Magnesium's electron configuration is [Ne] 3s² (1s² 2s² 2p⁶ 3s²), with 2, 8, 2 electrons per shell.
Is magnesium a metal?
Yes. Magnesium is an alkaline earth metal, one of the metals.
What is the melting point of magnesium?
Magnesium melts at 923 K (649.9 °C, 1201.7 °F) and boils at 1363 K (1089.8 °C, 1993.7 °F).
What is magnesium used for / known for?
A light structural metal that burns with a brilliant white flame and sits at the centre of every chlorophyll molecule.