Name the alkali metals in order of increasing atomic masses and write their electronic configurations.

The mobilities of alkali metal ions in aqueous solution are: ${\text{Li}}^{+}<{\text{Na}}^{+}<{\text{K}}^{+}<{\text{Rb}}^{+}<{\text{Cs}}^{+}$.
 

Comment on the following- Lithium is the only alkali metal to form a nitride directly.