Group 2

Seite 1

The atomic radius increases down the group because each element has an extra filled main level of electrons.

The melting point decreases down the group as the sea of delocalised electrons are further from the positive nucleus.

The first and second ionisation energies decreases down the group as the outer electrons are further from the nucleus so are easier to remove.

The metals get more reactive with water going down the group.

M + 2H20 => M(OH)2 + H2 (M = any group 2 metal)

Magnesium reacts very slowly with cold water but rapidly with steam to form hydrogen and Magnesium Oxide.

Calcium reacts in the same way but more vigorously, and barium even more so.

Going down the group, the hydroxides become more soluble. Barium hydroxide dissolves to produce hydroxide and barium ions.

Going down the group, the sulphates become less soluble.