12Mg24.305
Magnesium
Alkaline earth metalsReactive metals with two outer electrons, found in rocks, shells and bones.
[Ne] 3s²
- Atomic number
- 12
- Atomic mass
- 24.305
- Protons
- 12
- Neutrons
- 12 (most common)
- Electrons
- 12
- Shells
- 2, 8, 2
- State at 25 °C
- Solid
- Position
- Group 2, period 3
Proton (+)Neutron (0)Electron (−)
Discovered byJoseph Black, 1755 (isolated by Humphry Davy, 1808)Humphry Davy: 7 elementsJoseph Black: 1 element
Black recognised magnesium as an element. Davy isolated the metal using electricity. The name comes from Magnesia, a region of Greece.
Did you know?
- It burns with a dazzling white light.
- Every chlorophyll molecule has a magnesium atom at its centre.
Where it's found
- Seawater
- Rocks like dolomite
- Chlorophyll in green leaves
What it's used for
- Fireworks and flares
- Light alloys for bikes and laptops
- Antacid medicines
Try it
Epsom salt frostSafe at home
- 1Dissolve Epsom salt (magnesium sulfate) in a little warm water.
- 2Add a drop of dish soap and brush it onto a glass or window.
- 3Let it dry.
What you'll see: Feathery crystals spread across the glass like frost.