Question

Lattice energy of ionic compounds depend upon:
A.Packing of ions only
B.Charge and size of ions
C.Charge on ion only
D.Size of ions only

Answer 1

Hint: Lattice energy can be understood as the amount of energy required to remove or separate one mole of an ionic solid into its gaseous ions. To explain this concept in simpler terms, it is basically an estimated value of the bond strength in ionic compounds.

Complete Step-by-Step Answer:
Before we move forward with the solution of the given question. Let us first understand some important basic concepts.
A lattice can be understood as the spatial arrangement of atoms, molecules, or ions of a given compound which can be either uniform or non – unform in nature. The lattice forms the basis of the macro physical structure of the given compound.
Now, it can be defined as the heat of formation of ions which have opposite charges in the gas phase, to combine with each other to form an ionic solid.
There are certain factors which affect the value of the lattice energy. Charge on the ions relates to the forces of attraction present in the lattice. Hence, higher the charge, higher would be the lattice energy. On the other hand, the size of ions determines the distances between the ions. Greater ionic sizes result in farther placement of the ions from each other and would hence reduce the effective forces of attraction between them. Hence, the lattice energy is inversely proportional to the size of the ions.
Hence, lattice energy of ionic compounds depends upon both the charge and size of ions.
Hence, Option B is the correct option

Note: Isolation of individual gaseous ions is quite complex and often not possible. Because of this, lattice energy cannot be calculated via direct experimentation. The value of the lattice energy can be estimated using a process known as Born – Haber cycle.