The lattice site in a pure crystal cannot be occupied by _________.
(i) molecule
(ii) ion
(iii) electron
(iv) atom
The answer is the option (iii) electron
Pure crystals have constituents i.e., atoms, molecules, or ions arranged in a highly ordered microscopic structure in fixed stoichiometric ratio. Lattice sites can be occupied by electron only when there is imperfection in solid. They do not occur in pure crystals. Hence, the lattice site in a pure crystal cannot be occupied by electron. It is feasible only in case of imperfection giving rise to Crystal defects.