Magnesium is similar to sodium and potassium in toxicity towards human tissue in that the pure metal is toxic to cells, while the ions are not only unharmful but also function as cofactor for several key enzymes in the body.
This behaviour of magnesium is similar to that of calcium ions which are also required by the body mainly for bone tissue formation. A cofactor is a metal ion that helps the specific enzyme in its function in catalyzing the biochemical reactions.
Magnesium is located below beryllium in the periodic table and next to sodium in the right side. Its electronic configuration is similar to sodium with an additional electron that is located in an 3s orbital. Its configuration is [Ne]3s2. This configuration can easily loose two electrons from the 3s orbital to obtain the neon atom electronic configuration.
This can explain the formation and the stability of the magnesium +2 ion. The magnesium ion has an electronic configuration that of a noble gas which is inert for reactions under normal conditions.
The chemical behaviour of the magnesium column of metals is similar to that of the alkali metals. Magnesium ion has an ionic diameter which is approximately similar to that of lithium ion. Therefore the chemistry of both of these ions is similar.
This similarity is seen for example in the solubility parameters of LiF and MgF2 which are both hardly soluble in water. Both lithium and magnesium form nitrides with nitrogen.
Nitrogen molecule is a stable compound with a triple bond. Therefore it is considered to be inert. However, Li and Mg do react with nitrogen molecules to give nitrides.
Compounds of magnesium are known and have been prepared also. Magnesium hydroxide is a base which is used to neutralize acids. Magnesium hydride or MgH2 is a reducing agent and hydride donor. This compound generates hydrogen molecule when reacted with water.
Magnesium sulfate or MgSO4 is a compound that find uses in organic chemistry as a drying agent due to its hygroscopic nature. It can absorb water if present in the solution. In addition MgSO4 has application in the pharmaceutical industry. It is used there as a laxative.
Magnesium finds extensive use in organic chemistry. It main use in organic chemistry is in the well known Grignard reaction which is a reaction to generate C-C or carbon-carbon bonds. Alkyl halides add in an oxidative fashion to magnesium metal to generate alkyl magnesium halide. The net result of this addition is the conversion of an electrophile to a nucleophile.
Alkyl Gringard has been used extensively in organic reactions. Some of its use is the reaction of alkyl Gringard with epoxides to generate the alcohol. Another use is the addition of alkyl Gringard to ketones to generate the alcohols also.
Magnesium occurs naturally as MgCO3 or magnesium carbonate and magnesium sulfate and to a lesser extent as magnesium silicate. Magnesium metal is generated by electrolysis of MgCl2 or magnesium dichloride.
Mg has an atomic number of 12 and has 3 naturally occuring isotopes. Its ionization energy is higher than that of sodium because of the increase in nuclear charge as we move to the right in the periodic table. Magnesium releases its outermost electrons more readily than beryllium. It reacts readily with many nonmetals such as the halogens.