The hydroxides and carbonates of sodium and potassium are easily soluble in water while the corresponding salts of magnesium and calcium are sparingly soluble in water.

Explanation:

⇒ Due to larger size of Na and K as compared to that of magnesium and calcium, the lattice energies of hydroxides and carbonates of sodium and potassium are much lower than those of hydroxides and carbonates of magnesium and calcium.

⇒ As a result, the hydroxides of Na and K are easily soluble in water while that of corresponding salts of magnesium and calcium are sparingly soluble in water.

Note: Lattice Energy is defined as the amount of energy released when cations and anions are brought from infinity to their respective equilibrium sites in the crystal lattice to form a compound. Lower the lattice energy of a compound, higher will be the solubility.