Sodium chloride crystallizes with Na+ ions (ionic radius ≈ 102 pm) and Cl− ions…
CHEMISTRY · Single correct · ISC · Chemistry · Chemical Bonding and Molecular Structure · Chemical Bonding and Molecular Structure
Problem
Sodium chloride crystallizes with Na+ ions (ionic radius ≈ 102 pm) and Cl− ions (ionic radius ≈ 181 pm). If 10 % of the Na+ ions are replaced by K+ ions (ionic radius ≈ 138 pm) to form Na0.9K0.1Cl, which of the following best predicts the effect of this substitution on the magnitude of the lattice energy?
(a) It increases because the crystal becomes more polarizable.
(b) It remains essentially unchanged because the cations still carry a +1 charge.
(c) It decreases because the average cation–anion separation distance increases.
(d) It increases because the larger cation allows stronger ionic interactions due to its greater surface area.