Group Two -

When group two elements react they form ions with a charge of 2+, which is because they contain 2 electrons in their outer shell.

E.g : M -> M2+ + 2e-

       Ca -> Ca2+ + 2e-

The group 2 metals react with water to give a metal hydroxide and hydrogen

E.g : M (s) + 2H20 (l) --> M(OH)2 (aq) + H2 (g)

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

Group 2 become increasingly reactive down the group because the outermost electrons are further away from the nucleous and so are more easily lost.

Form Alkaline Solutions in H20

1. Oxides of group 2 metals react readily with water to form metal hydroxides, which dissolve. Hydroxide ions OH- make the solutions strongly alkaline.

E.g: CaO (s) + H2O --> Ca2 (aq) + 2OH- (aq)

2. MgO is an exception - it reacts really slowly, and the hyrdoxide isnt very soluble.

3. Oxides form more strongly alkaline solutions as you go down the group, which is because the oxides become more soluble.

Because they are bases, both the oxides and hydroxides neutralise dilute salts  forming solutions of the corresponding salts.

MgO(s) + 2HCl --> H2O (l) + MgCl2 (aq)

Mg(OH)2 (s) + 2HCl --> 2H2O + MgCl2 (aq)