Down the group the melting points decrease. The metallic bonding weakens as the atomic size increases. The distance between the positive ions and delocalized electrons increases. Therefore the electrostatic attractive forces between the positive ions and the delocalized electrons weaken.

The outermost electrons are held more weakly because they are successively further from the nucleus in additional shells. In addition, the outer shell electrons become more shielded from the attraction of the nucleus by the repulsive force of inner shell electrons

increases down the group

Mg burns with a bright white flame. MgO is a white solid with a high melting point due to its ionic bonding.

2Mg + O2 ----> 2MgO

Magnesium burns in steam to produce magnesium oxide and hydrogen. The Mg would burn with a bright white flame

Mg (s) + H2O (g) ----> MgO (s) + H2 (g)

Mg + 2 H2O ----> Mg(OH)2 + H2 This is a much slower reaction than the reaction with steam and there is no

Ca + 2 H2O (l)---> Ca(OH)2 (aq) + H2 (g)

Sr + 2 H2O (l)----> Sr(OH)2 (aq) + H2 (g)

Ba + 2 H2O (l)----> Ba(OH)2 (aq) + H2 (g)

fizzing, (more vigorous down group) the metal dissolving, (faster down group) the solution heating up (more down group) and with calcium a white precipitate appearing (less precipitate forms down group)

it is abundant, has a low density and is corrosion resistant – it is used for making strong, light alloys for use in aircraft

Titanium is extracted by reaction with a more reactive metal Mg Na

titanium carbide (TiC) it is formed rather than titanium.