Which of the following statements is not true for lithium ?

→ Due to its small size, it has greater inter atomic attractions and hence "Li" is hardest metal in the I_A group.
→ Li easily reacts with atmospheric nitrogen and forms Li₃N,Where as remaining elements of the same group they can't form nitrides at room temperature.
→ Li in aqueous solution acts as strongest reducing agent among all metals
Reason
The hydration energy of Li⁺ is greater than the of sum of Ionisation and sublimation energies, as a result of this the lithium 

 $\left[{\mathrm{E}}_{\raisebox{1ex}{$\mathrm{Li}$}\!\left/ \!\raisebox{-1ex}{${\mathrm{Li}}^{+}$}\right.}^{\mathrm{o}}\right]$  electrode potential is very high + 3.04volts

$$\begin{gathered} {\mathrm{Li}}_{\left(\mathrm{s}\right)}\stackrel{+\mathrm{SE}}{\to }{\mathrm{Li}}_{\left(\mathrm{g}\right)} \\ {\mathrm{Li}}_{\left(\mathrm{g}\right)}\stackrel{+\mathrm{IE}}{\to }{\mathrm{Li}}_{\left(\mathrm{g}\right)}^{+} \\ {\mathrm{Li}}_{\left(\mathrm{g}\right)}^{+}+{\mathrm{nH}}_2\mathrm{O}\stackrel{-\mathrm{HE}}{\to }{\mathrm{Li}}^{+}{\left[{\mathrm{H}}_2\mathrm{O}\right]}_{\mathrm{n}} \end{gathered}$$

HE > [S.E + I.E]
→ Due to  [Li] small size and high polarising power of Li⁺ ion, its compounds possess greater covalent character
 

$\mathrm{Polarising} \mathrm{power}\propto \mathrm{Covalent} \mathrm{character}\propto \frac{1}{\mathrm{Size} \mathrm{of} \mathrm{ion}}$

Note : The ability of a cation to cause distrotion in anion is called polarising power.