All of the metals react similarly to give white, ionic chlorides. Reactions of the alkaline earth metals with water. Strontium and barium react similarly, the reaction of barium being vigorous and giving a colourless solution of barium hydroxide the most soluble of the group 2 hydroxides. Reactions of group 1 and group 2 oxides with cold water. The superoxides of rubidium and caesium react similarly.
Calcium oxide reacts very exothermically.
Reactions of group 1 and group 2 oxides with dilute acids. The superoxides of rubidium and caesium react similarly. All the group 2 oxides react similarly except with sulphuric acid. In this case magnesium oxide reacts as given, but the sulphates of Ca Ba are insoluble. The oxide therefore reacts superficially but reaction then ceases.