Identify the correct decreasing order of lattice enthalpy for metal fluorides from following.

Step-by-step solution

Lattice enthalpy is directly proportional to the product of charges of the ions and inversely proportional to the internuclear distance between them. U q₁ q₂ r_+ + r_- For alkali metal fluorides, the charges on the ions are the same (+1 and -1). The ionic radius of alkali metal cations increases down the group in the order: Li ^+ As the size of the cation increases, the internuclear distance increases, which leads to a decrease in the lattice enthalpy. Therefore, the decreasing order of lattice enthalpy is LiF > Na