The lattice energies of KF, KCl, KBr and KI follow the order : — Chemical Bonding Chemistry Question

💡 Solution & Explanation

Step 1: Recall that lattice energy (U) is inversely proportional to the sum of the radii of the cation and anion (r_c + r_a). Step 2: For potassium halides KF, KCl, KBr, and KI, the cation (K^+) is the same, while the size of the halide anions increases in the order F^- < Cl^- < Br^- < I^-. Step 3: Since size is inversely proportional to lattice energy, KF (smallest anion) has the highest lattice energy and KI (largest anion) has the lowest. Thus, the correct order is KF > KCl > KBr > KI, which is option (a).