12 Mg 24.305

Magnesium

Alkaline Earth Metal

Magnesium (Mg) is a chemical element with atomic number 12, classified as a alkaline earth metal. At room temperature it is a solid. It was discovered in 1755 by Joseph Black.

Properties

Atomic number
12
Atomic mass
24.305 u
Category
Alkaline Earth Metal
Group
2
Period
3
Block
s-block
Electron configuration
[Ne] 3s²
Phase at STP
Solid
Density
1.738 g/cm³
Melting point
923 K (649.9 °C)
Boiling point
1363 K (1089.8 °C)
Electronegativity
1.31
Atomic radius
145 pm
Ionization energy
7.646 eV
Discovery
1755 · Joseph Black

Common uses

Lightweight alloys, fireworks, antacids, photography flashes

Did you know?

Burns with brilliant white light and is essential for chlorophyll in plants.