Magnesium is the twelfth element of the periodic table. These magnesium facts contain chemical and physical data along with general information and history.
Basic Magnesium Facts
Atomic Number: 12
Element Symbol: Mg
Element Family: alkaline earth
Atomic Mass: [24.304, 24.307]
IUPAC guidelines to reflect the physical and chemical history of the magnesium sample. If a single value of the atomic mass is needed, use 24.305.
Electron Configuration: [Ne]3s2 (shorthand) or 1s22s22p63s2 (full)
Discovery: Joseph Black in 1755 identified magnesium as an element. Sir Humphrey Davy isolated pure magnesium in 1808.
Many chemists believed lime (calcium oxide) and magnesia (magnesium oxide) were the same substance. Both were produced by heating limestone and magnesite. Black showed they each had different chemical properties. Magnesia contained an unknown element similar to calcium. Just over 50 years later, Davy separated magnesium from an amalgam of magnesia and mercury using electrolysis.
Name Origin: Davy named the element after its source material, magnesia.
Natural magnesium is comprised of three stable isotopes: 24Mg, 25Mg and 26Mg. Nineteen radioactive isotopes have been produced under laboratory conditions ranging from 19Mg to 40Mg.
Magnesium-24 is a stable isotope containing 12 neutrons. 78.99% of natural magnesium is magnesium-24.
Magnesium-25 is a stable isotope containing 13 neutrons. 10% of natural magnesium is magnesium-25.
Magnesium-26 is a stable isotope containing 14 neutrons. 11.01% of natural magnesium is magnesium-26.
Density: 1.74 g/cm3
Melting Point: 923 K (650 °C, 1202 °F)
Boiling Point: 1363 K (1091 °C, 1994 °F)
State at 20ºC: Solid
Heat of Fusion: 8.48 kJ/mol
Heat of Vaporization: 128 kJ/mol
Molar Heat Capacity: 24.869 J/mol·K
Atomic Radius: 1.6 Å
Covalent Radius: 1.41 Å
Van der Waals Radius: 1.73 Å
Electron Affinity: not stable
1st Ionization Energy: 737.75 kJ/mol
2nd Ionization Energy: 1450.683 kJ/mol
3rd Ionization Energy: 7732.692 kJ/mol
4th Ionization Energy: 10542.519 kJ/mol
5th Ionization Energy: 13630.48 kJ/mol
6th Ionization Energy: 18019.6 kJ/mol
7th Ionization Energy: 21711.13 kJ/mol
8th Ionization Energy: 25661.24 kJ/mol
Oxidation States: +2 (common), +1 (uncommon)
Fun Magnesium Facts
- Magnesium is a silvery-white alkaline solid at room temperature.
- Magnesium has a sour taste. Small amounts of magnesium in mineral water gives it that slightly sour flavor.
- An early name for magnesium was “magnium”. The metallic form of manganese was already known as magnesium. Davy was convinced by his colleagues to change the name to magnesium and manganese metal was just called manganese.
- Magnesium is a central atom in the chlorophyll molecule. It is an essential part of the process of photosynthesis.
- Magnesium is the ninth most abundant element in the universe.
- Magnesium is the eighth most abundant element in the Earth’s crust.
- Magnesium is the 11th most abundant element in the human body. There is magnesium in every one of your cells.
- 60% of the magnesium found in your body is found in your skeletal system.
- Magnesium burns very brightly and is used in fireworks to make white sparkles.
- Magnesium is added to alloys to reduce weight of aluminum materials.
- Magnesium is found in some firestarters to produce sparks when rubbed with steel.
- Magnesium hydroxide is added to some plastics to make them fire resistant.
- A class of organic magnesium compounds known as Grignard reagents are important compounds in synthesis reactions in organic chemistry. These compounds take the form: RMg-X, where R is a carbon functional group and X is a halide.
Learn more about elements on the periodic table.