Question

The lattice energy of LiF is 1023 kJ/mol, and the Li–F distance is 200.8 pm. NaF crystallizes in the same structure as LiF but with a Na–F distance of 231 pm. Which of the following values most closely approximates the lattice energy of NaF: 510, 890, 1023, 1175, or 4090 kJ/mol? Explain your choice.

Answer 1

The lattice energy of NaF can be estimated by comparing the distances between the ions and their charges.

Step-by-step explanation:

The lattice energy of a compound is a measure of the strength of the ionic bonds in the crystal lattice. It depends on the product of the charges of the ions and the distance between them. In this case, NaF has the same structure as LiF, but the Na-F distance is larger than the Li-F distance. Since the lattice energy is inversely proportional to the distance between ions, a larger distance will result in a lower lattice energy.

Therefore, the correct answer is 890 kJ/mol. This value is the closest approximation to the lattice energy of NaF.