MAGNESIUM

Symbol --- Mg

Abundance --- 2% in the earth’s crust.

Physical state (STP)--- solid

Elemental category --- alkaline earth metal

Colour --- shiny grey

Discovery --- Joseph Black

Atomic no --- 12

Atomic weight --- 24.305

Period --- 3

Group --- 2 or IIA

Block --- s block

Known isotopes --- ₁₂Mg¹⁹, ₁₂Mg²⁰, ₁₂Mg²¹, ₁₂Mg²², ₁₂Mg²³, ₁₂Mg²⁴, ₁₂Mg²⁵, ₁₂Mg²⁶, ₁₂Mg²⁷, ₁₂Mg²⁸, ₁₂Mg²⁹, ₁₂Mg³⁰, ₁₂Mg³¹, ₁₂Mg³², ₁₂Mg³³, ₁₂Mg³⁴, ₁₂Mg³⁵, ₁₂Mg³⁶, ₁₂Mg³⁷, ₁₂Mg³⁸

Main isotopes --- ₁₂Mg²⁴, ₁₂Mg²⁵, ₁₂Mg²⁶

Isotopic abundance --- ₁₂Mg²⁴(78.99%), ₁₂Mg²⁵(10.005%), ₁₂Mg²⁶(11.005%)

Melting Point --- 650 ⁰C (923.15 K)

Boiling Point --- 1090 ⁰C (1363.15 K)

Heat of Fusion --- 8.47 KJ/mol

Heat of Vaporisation --- 127.5 KJ/mol

Molar heat capacity --- 24.855 J/(mol-K)

Density --- 1.7 g/cm³

Molar volume --- 0.000013

Electron configuration --- [Ne] 3s²

Electrons per shell --- 2 (1 st shell), 8 (2 nd shell), 2 (3 rd shell)

Oxidation state --- +2

Valance --- 2

Electronegativity --- 1.31 (Pauling scale)

Ionisation energy --- 737 KJ/mol (1 st), 1450 KJ/mol (2 nd), 7731 KJ/mol (3 rd), 10542 KJ/mol (4 th)

Covalent radius --- 141 pm

Atomic radius --- 160 pm

Van der Waals radius --- 173 pm

Radius of Mg²⁺ (6-coordinated) --- 72 pm

E⁰(V) for [Mg²⁺(aq)/Mg(s)] --- – 2.37

Natural occurrence --- primordial

Crystal structure --- hexagonal close packed (hcp)

Specific heat --- 1020 J/(Kg K) (solid phase)

Thermal expansion --- 24.9 μm/(m-K) (at 298 K)

Thermal conductivity --- 156 W/(m-K)

Electrical resistivity --- 43.8 nΩ-m (at 293K)

Speed of sound --- 4939 m/s (at 298 K)

Magnetic type --- paramagnetic

Mass magnetic susceptibility --- 6.88 x 10^-9 m³/Kg

Molar magnetic susceptibility --- 1.69 x 10^-10 m³/mol

Volume magnetic susceptibility --- 1.2 x 10^-5

Mohs hardness --- 2.5

Brinell hardness --- 260 MPa

Poisson ratio --- 0.29

Young’s modulus --- 45 Gpa

Shear modulus --- 17 GPa

Bulk modulus --- 35.5 GPa 

Lattice angles --- π/2, π/2, 2π/3

Lattice constants --- 320.88 pm, 320.88 pm, 521.09 pm

Quantum numbers --- ¹S₀

Neutron cross section --- 6.3 x 10^-2

Neutron mass absorption --- 1 x 10^-4