Periodic TableAll elementsMagnesium
No. 012
Mg
24.305 u
Element · Alkaline Earth

Magnesium

Magnesium (镁, symbol Mg) is chemical element number 12, an Alkaline Earth in period 3, group 2 of the periodic table, with a standard atomic weight of about 24.305. Shiny gray metal, key to chlorophyll and used in lightweight structural alloys.

Period 3Group 2[Ne] 3s²

Properties

Atomic number12
SymbolMg
Atomic mass24.305 u
CategoryAlkaline Earth
Period3
Group2
Electron configuration[Ne] 3s²
Electronegativity1.31
Covalent radius141 pm
Density1.738 g/cm³
Melting point923 K
Boiling point1363 K
DiscoveryJoseph Black, 1755

Overview

Shiny gray metal, key to chlorophyll and used in lightweight structural alloys. Magnesium (symbol Mg) is chemical element number 12, sitting in period 3, group 2 of the periodic table and classed as an Alkaline Earth. As an alkaline-earth metal it is a little less reactive than the alkali metals and occurs in nature mainly within mineral compounds.

It has the configuration [Ne] 3s² and an electronegativity near 1.31; its 2 outer-shell electrons drive its bonding. Under standard conditions it exists as a solid; it melts near 923 K (649.9 °C), boils near 1363 K (1089.9 °C), has a density around 1.738 g/cm³.

It is widely used in Structural / Alloys, Medical / Pharma and Agriculture / Fertiliser. It is regarded as a moderate-hazard element, so handle it with appropriate care. It was first described by Joseph Black in 1755. See more trends in the visualization center.

Electron shells

Mg12

Electrons per shell: 2 · 8 · 2

Main uses

Hazard

ModerateFlammable

Compounds containing Magnesium

No compounds in this knowledge base contain Magnesium yet.

Data sources

Atomic mass uses IUPAC (CIAAW) standard atomic weights; the covalent radius is from Cordero et al. (2008). Verify on the RSC Periodic Table, PubChem and Wikipedia. Educational reference only.