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Magnesium (Mg)

Magnesium is a chemical element of the periodic table with chemical symbol Mg and atomic number 12 with an atomic weight of 24.304 u and is classed as alkaline earth metal and is part of group 2 (alkaline earth metal). Magnesium is solid at room temperature.

Magnesium in the periodic table

Atomic number12
Group2 (Alkaline earth metal)
ClassificationAlkaline Earth Metal
AppearanceShiny grey solid
Color Silver
Number of protons12 p+
Number of neutrons12 n0
Number of electrons12 e-
From Wikipedia, the free encyclopediaMagnesium is a chemical element with symbol Mg and atomic number 12. It is a shiny gray solid which bears a close physical resemblance to the other five elements in the second column (Group 2, or alkaline earth metals) of the periodic table:they each have the same electron configuration in their outer electron shell producing a similar crystal structure. Magnesium is the ninth most abundant element in the universe.

Physical properties

Phase at STPSolid
Density1.738 g/cm3
Atomic weight24.304 u

Thermal properties

Melting point923 K
649.85 °C
1201.73 °F
Boiling point1363 K
1089.85 °C
1993.73 °F
Heat of vaporization127.6 kJ/mol

Atomic properties

Electronegativity (Pauling Scale)1.31
Electron affinity-40 kJ/mol
Oxidation states+1, +2
(a strongly basic oxide)
Ionization energies
  1. 737.7 kJ/mol
  2. 1450.7 kJ/mol
  3. 7732.7 kJ/mol
  4. 10542.5 kJ/mol
  5. 13630 kJ/mol
  6. 18020 kJ/mol
  7. 21711 kJ/mol
  8. 25661 kJ/mol
  9. 31653 kJ/mol
  10. 35458 kJ/mol
  11. 169988 kJ/mol
  12. 189368 kJ/mol

Electron configuration for magnesium

Electron configuration
Shorthand configuration
[Ne] 3s2
Electron configuration
Full configuration
1s2 2s2 2p6 3s2
Electron configuration chart
Electrons per shell2, 8, 2
Valence electrons 2
Valency electrons 2
Bohr model
MagnesiumElectron shell for Magnesium, created by Injosoft ABMg
Figure: Shell diagram of Magnesium (Mg) atom.
Orbital Diagram

The history of Magnesium

DiscoveryJoseph Black (1755)
First isolationHumphry Davy (1808)
Discovery of magnesium
The name magnesium originates from the Greek word for locations related to the tribe of the Magnetes, either a district in Thessaly called Magnesia or Magnesia ad Sipylum, now in Turkey. The metal was first isolated by Sir Humphry Davy in England in 1808. He used electrolysis on a mixture of magnesia and mercuric oxide. Antoine Bussy prepared it in coherent form in 1831. Davy's first suggestion for a name was magnium, but the name magnesium is now used in English and all major European languages but Russian.


List of unique identifiers for Magnesium in various chemical registry databases
CAS Number7439-95-4
ChemSpider ID4575328
EC number231-104-6
PubChem CID Number5462224