The table lists the lattice energies of some compounds. Compound
Lattice Energy (kJ/mol)
LiF –1,036
LiCl –853
NaF –923
KF –821
NaCl –786

Which statement about crystal lattice energy is best supported by the information in the table?
The lattice energy increases as cations get smaller, as shown by LiF and KF.
The lattice energy increases as the cations get larger, as shown by LiF and LiCl.
The lattice energy decreases as cations get smaller, as shown by NaCl and NaF.
The lattice energy decreases as the cations get smaller, as shown by NaF and KF.

The lattice energy increases as cations get smaller, as shown by LiF and KF.

Explanation:

Lattice energy is the change in internal energy that accompanies the formation of one mole of the solid from its constituent gas phase ions at 0 K. In calculating the lattice energy, we assume an electrostatic model where the ions are regarded as point charges.

The size of the ions determines the magnitude of the lattice energy. If the anion is the same, then the magnitude of the lattice energy depends on the the size of the cation, the smaller the cation the greater the lattice energy.

Since Li^+ is smaller than K^+, it is expected that LiF will have a greater lattice energy than KF, hence the answer.

The statement about crystal lattice energy that is supported by the information in the table is A. The lattice energy increases as cations get smaller, as shown by LiF and KF.

It should be noted that lattice energy simply means the change in internal energy that occurs after the formation of one mole of the solid from its constituent gas phase ions.

The magnitude of the lattice energy is determined by the size of the ions. From the table, the lattice energy increases as cations get smaller, as shown by LiF and KF.

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