The hydration energy of Mg2+ ions is lesser than that of : — Periodic Table and Periodicity Chemistry Question

💡 Solution & Explanation

Step 1: Hydration energy is directly proportional to the charge density of the ion (charge of ion / ionic size). Step 2: Aluminium (Al^3+) possesses a higher positive charge (+3) and a smaller ionic radius compared to Magnesium (Mg^2+). Step 3: Because of its higher charge density, the hydration energy of Al^3+ is significantly greater than that of Mg^2+. Thus, the hydration energy of Mg^2+ is lesser than that of Al^3+, corresponding to option (a).