Question

The relation between the magnitudes of lattice energy of crystal and its formation energy is:

• A. lattice energy > formation energy
• B. lattice energy $=$ formation energy
• C. lattice energy < formation energy
• D. none of the above

Answer 1

Answer: (B)

lattice energy $=$ formation energy

Lattice energy is the energy required to break apart an ionic solid and convert its component atoms into gaseous ions. The value of the lattice energy to always be positive.

Also, enthalpy of lattice formation is defined as the energy released when gaseous ions bind to form an ionic solid. The value is negative but has the same magnitude as lattice energy.

Hence, $B$ is correct.