Question
Answers

Lattice energy of an ionic compound depends upon:
(A) Charge on the ions only
(B) Size of the ions only
(C) Packing of the ions only
(D) Charge and size of the ions

Answer Verified Verified
Hint- Before going through the given factors on which lattice energy depends we will first define the lattice energy of an ionic compound with some examples. Lattice energy is an estimation of the strength of bonds in ionic compounds.

Complete answer:
> In the gas phase, it is defined as the heat of formation for opposite charge ions to be combined into an ionic solid. As an example , sodium chloride's lattice energy, NaCl, is the energy released when gaseous $N{a^ + }$ and $C{l^ - }$ ions join together to form a lattice of alternating ions in the NaCl crystal.
> The two main factors contributing to an ionic solid lattice energy: is the charge on the ions and the ion radius, or size.
- As charge on ions increases, the energy of the lattices increases.
- As the ion size increases, the energy from the lattices decreases.
- As it is clear that the lattice energy depends upon the charge of the ions
Hence, the correct option is D.

Note- Lattice energy cannot be experimentally determined because of the difficulty of isolating gaseous ions. The energy value can be estimated using the Born-Haber cycle, or can be theoretically calculated using an electrostatic examination of the crystal structure. The energy required to separate the mole of an ionic solid into the gaseous form of its ions can be considered as lattice energy.