Chemistry - Complete s-block Question with Solution | TestHub

(A) The sulphates of the alkaline earth metals are all white solid and stable to heat. ${\mathrm{BeSO}}_4$ and ${\mathrm{MgSO}}_4$ are readily soluble in water; the solubility decreases from ${\mathrm{CaSO}}_4$ to ${\mathrm{BaSO}}_4$. The greater hydration enthalpies of ${\mathrm{Be}}^{2+}$ and ${\mathrm{Mg}}^{2+}$ ions overcome the lattice enthalpy factor and therefore their sulphates are soluble in water.

(B) Hydration energy of alkaline earth metal ions decrease with increase in ionic size down the group and the order is, ${\mathrm{Be}}^{2+}>{\mathrm{Mg}}^{2+}>{\mathrm{Ca}}^{2+}>{\mathrm{Sr}}^{2+}>{\mathrm{Ba}}^{2+}$.

(C) The thermal stability of oxy-acid salts of alkaline earth metals generally increases down the group with increasing metallic character, i.e. electropositive character.

(D) Hydration energy of alkaline earth metal ions decrease with increase in ionic size down the group so the order of their ionic radius in water is, ${\mathrm{Be}}^{2+}<{\mathrm{Mg}}^{2+}<{\mathrm{Ca}}^{2+}<{\mathrm{Sr}}^{2+}<{\mathrm{Ba}}^{2+}$.