The general characteristics of all these elements generally preclude
their extraction by any method involving aqueous solution. For the
lighter, less volatile metals (Li, Na, Be, Mg, Ca) electrolysis of a
fused salt (usually the chloride), or of a mixture of salts, is used.
The heavier, more volatile metals in each group can all be similarly
obtained by electrolysis, but it is usually more convenient to take
advantage of their volatility and obtain them from their oxides or
chlorides by displacement, i.e. by general reactions such as