The table below lists three crystalline chlorides along with the ionic (crystal)…
CHEMISTRY · Multi-part · CBSE · Chemistry · Chemical Bonding and Molecular Structure · Chemical Bonding and Molecular Structure
Problem
The table below lists three crystalline chlorides along with the ionic (crystal) radii of their constituent ions.
Compound | Radius of cation / pm | Radius of anion (Cl⁻) / pm
LiCl | 76 | 181
KCl | 152 | 181
MgCl₂ | 72 (Mg²⁺) | 181
Assume that the chloride ion occupies identical lattice sites in all three compounds.
Use the information provided to analyze the relative magnitude of the electrostatic interactions in these lattices.
(a) Rank the three compounds from greatest to least magnitude of lattice energy. Provide your ranking clearly.
(b) Justify the ranking in part (a) by explicitly discussing both ionic charge and internuclear separation for each compound.
(c) Predict which compound is expected to have the highest melting point. Explain how your answer is consistent with your reasoning in part (b).