Answer:
The answer is NaF.
Explanation:
Lattice energy:
It can be define as "the amount of energy released when ions combine to from the ionic solids or energy required to break the compound into its ions"
Example:
Consider the example of ionic solid NaCl. The sodium chloride is formed when ions like Na+ and Cl - are combine. During the formation of NaCl crystals the energy is released which is called lattice energy of sodium chloride.
Dependence of lattice energy:
Lattice energy depend upon following factors:
1. Charges of the ions
2. Sizes of the ions
As the charge of ion increase the lattice energy also increase. There is a direst relationship between them.
The size of the ions and lattice energy have inverse relation. As the size decreases, lattice energy increases. Therefor, the compound NaF consist of smallest cation (Na+) and the smallest anion (F-) have largest lattice energy.
F= q1 × q2/ r²
As the size of ions decreases the distance between the oppositely charged ions in a ionic compound decreases. They will more tightly packed in a crystal and their center will more closer to each others hence increase the lattice energy.