12Mgmagnesio–magnesiumMass: 24,3247u[Ne]3s2 Melting point:923 KBoiling point: 1363KDensity: 1738 kg/m3Discovery: Joseph Black. Its common oxidation number is +2. It is an alkaline earth metal.Magnesium is the fourth most common element in the Earth as a wholemaking up 13% of the planets mass and a large fraction of the planetsmantle. . Due to magnesium ions high solubility in water, it is the thirdmost abundant element dissolved in seawater.