What are the causes of conductors in solids?

Causes of Conductance in solids

(1)    In most of the solids, conduction is through electron movement under an electric field.

(2)    In ionic solids conduction is by movement of ions.

(3)    The magnitude of electrical conductivity strongly depends upon the number of electrons available to take part in the conductive process.

(4)    In metals, conductivity strongly depends upon the number of electrons available per atom.

(5)    If conduction band is not completely filled or it lies very close to a higher unoccupied band, then electrons can flow easily under an electric field thereby showing conductivity.

(6)    In case of insulators, the gap between valence band and conduction band is too large, so electrons cannot jump from valence band to conduction band and very small conductivity is observed