Question

Which of the following ions will have the highest lattice energy?

• A. \( \text{NaCl} \)
• B. \( \text{MgO} \)
• C. \( \text{KCl} \)
• D. \( \text{LiF} \)

Hint:

Remember: Lattice energy increases with higher charges and smaller ionic radii.

Answer 1

The Correct Option is B

Step 1: Define lattice energy
Lattice energy is the energy released when one mole of an ionic compound forms from its gaseous ions. Higher lattice energy is observed with smaller ions and higher ionic charges.
Step 2: Analyze ionic compounds
- \( \text{NaCl} \) consists of Na\( ^+ \) and Cl\( ^- \) (charge of \( 1 \)).- \( \text{MgO} \) consists of \( \text{Mg}^{2+} \) and \( \text{O}^{2-} \) (charge of \( 2 \)).- \( \text{KCl} \) consists of K\( ^+ \) and Cl\( ^- \), where K\( ^+ \) is larger than Na\( ^+ \).- \( \text{LiF} \) consists of \( \text{Li}^{+} \) and F\( ^- \). Its ions are smaller than those in NaCl, but the charges are \( 1 \).
Step 3: Determine highest lattice energy
Comparing these compounds, \( \text{MgO} \) exhibits ions with the highest charges (2+ and 2-) and smaller ionic radii than \( \text{NaCl} \), \( \text{KCl} \), and \( \text{LiF} \). Consequently, \( \text{MgO} \) will possess the highest lattice energy.
Answer:
Therefore, \( \text{MgO} \) will have the highest lattice energy. The correct answer is option (2).