The lattice site in a pure crystal cannot be occupied by ......... .

1.  Molecule

2.  Ion

3.  Electron

4.  Atom

 

Each point in a lattice is known as lattice point which are either atom or molecule or ion which are joined together by a straight line to bring out geometry of lattice in pure crystal constituents are arranged in fixed stoichiometric ratio. Hence, existence of free electrons are not possible, it is possible on in case of imperfection of solid.