The difference between conductors and insulators is because
of electronic structure of atoms and molecules.
Anywhere we have free electrons, we have a hard conductor
where free electrons help in conduction.
In electrolytes, charged Ions do conduction.
Dielectrics (or insulators) don't have free electrons current.
Free electrons mean, the electrons that are not related with
a specific atom, they are allowed to move nearby the crystal lattice.
