Question

Which of the following compounds contains the most lattice energy?

1) KCl
2) BaCl2
3) CaS
4) Na₂⁺O

Answer 1

CaS contains the most lattice energy among the given compounds.

Step-by-step explanation:

The compound with the largest lattice energy can be determined based on the charges of the ions and the relative sizes of the ions in the compound. Lattice energy is directly proportional to the product of the ionic charges and inversely proportional to the internuclear distance.

Among the given compounds:

1. KCl: The charges of the ions are +1 and -1. The internuclear distance is determined by the sizes of the ions, which are relatively smaller compared to the ions in other compounds.
2. BaCl2: The charges of the ions are +2 and -1. The internuclear distance in this compound is larger than that in KCl, as Ba²+ is larger than K+.
3. CaS: The charges of the ions are +2 and -2. The internuclear distance in this compound is smaller than that in BaCl2, as Ca²+ is smaller than Ba²+.
4. Na₂O: The charges of the ions are +1 and -2. The internuclear distance in this compound is larger than that in CaS, as Na⁺ is larger than Ca²+.

Therefore, CaS contains the most lattice energy among the given compounds.