Hydration enthalpy of ${\mathrm{Li}}^{+}$ is lesser than that of ${\mathrm{Be}}^{+2}$. Lithium is the best reducing agent among alkali metals in aqueous solutions. The best reducing agent among second group elements in aqueous solution is

Hydration enthalpy(exothermic) of ${\mathrm{Be}}^{+2}$ is high but at the same time the sum of ${\mathrm{IP}}_1$, and ${\mathrm{IP}}_2$(endothermic) is also very high;

$\therefore$the process, $\mathrm{M}\left(\mathrm{s}\right)\stackrel{+{\mathrm{\Delta H}}_{\mathrm{sub}}}{\to }\mathrm{M}\left(\mathrm{g}\right)\stackrel{+{\mathrm{\Delta H}}_{{\mathrm{IE}}_1}}{\to }{\mathrm{M}}^{+}\left(\mathrm{g}\right)\stackrel{+{\mathrm{\Delta H}}_{{\mathrm{IE}}_2}}{\to }{\mathrm{M}}^{+2}\left(\mathrm{g}\right)\stackrel{+{\mathrm{\Delta H}}_{\mathrm{Hyd}}}{\to }{\mathrm{M}}^{+2}\left(\mathrm{aq}\right)$ is not so feasible in the case of beryllium in aqueous solution;

The reducing power of Be < Mg < Ca < Sr < Ba $\approx$ Ra