Group IIA Be, Mg, Ca, Sr, Ba, Ra

Group IIA metals inelude Be, Mg, Ca, Sr, Ba and Ra whieh are grey, moderately-hard, high melting-point substanees. Like the alkali metals they attaek water to liberate hydrogen but with less vigour. The salts of the alkaline earths are generally less stable towards heat and water than those of alkali metals, and less water soluble. 

Abstract This chapter explains what the rare earth elements are, where and when they were discovered, and by whom. The name of each element is explained (as the elemental names are rather exotic), the misleading name for these metals, which suggests that they are rare (which they are not), is clarified, and the fact that they are not earth metals is established. The alkaline earth metals constitute group IIA in the periodic system, consisting of Be, Mg, Ca, Sr, Ba, and Ra the rare earth elements are transition metals (group lllB). 

Reactions of Rb and Cs with oxygen also give superoxides. Group IIA metals follow a similar pattern. Be, Mg, Ca, and Sr give normal oxides, and Ba gives predominantly the peroxide. Apparently, Ra gives either a peroxide or some superoxide depending on the reaction conditions. 

The group IIA metals have the outer electron configuration ns2 with no singly occupied orbital for bonding. The structures are hep for Be and Mg and ccp for Ca and Sr. The structures are bcc for Ba and Ra, for which promotion to (n — l)d1ns1 is more favorable than for the other metals of the family. Metals with filled or nearly filled orbitals (Co, Ni, Pt metals, Cu family, Zn, and Cd) have ccp (3P) or hep (2P) structures. 

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