Beryllium shows diagonal relationship with

Identify the ions which form hydrated chlorides from the following:

$\mathrm{a})$ ${\mathrm{Ba}}^{2+}$
$\mathrm{b})$ ${\mathrm{Li}}^{+}$
$\mathrm{c})$ ${\mathrm{Sr}}^{2+}$
$\mathrm{d})$ ${\mathrm{Cs}}^{+}$
$\mathrm{e})$ ${\mathrm{Mg}}^{2+}$
$\mathrm{f})$ ${\mathrm{Rb}}^{+}$
$\mathrm{g})$ ${\mathrm{Ca}}^{2+}$

Given below are two statements:

Statement I : The chlorides of $\mathrm{Be}$ and $\mathrm{Al}$ have Cl-bridged structure. Both are soluble in organic solvents and act as Lewis bases.

Statement II: Hydroxides of $\mathrm{Be}$ and $\mathrm{Al}$ dissolve in excess alkali to give beryllate and aluminate ions. In the light of the above statements. Choose the correct answer from the options given below.

Among the statement (I – IV), the correct ones are:

(I) Be has smaller atomic radius compared to Mg.

(II) Be has higher ionization enthalpy than AI.

(III) Charge/radius ratio of Be is greater than that of Al.

(IV) Both Be and Al form mainly covalent compounds