Question

In a good conductor, the energy gap between the conduction band and the valence band is

Answer 1

The essential criterias for any solid to conduct electricity are
1. Presence of electrons in conduction band
2. Small gap between the valence and conduction band.
Generally, metals are good conductors of electricity.
The mobile electrons account for the high electrical conduction of metals. Electrical conduction takes place through a minor disturbance in energy, promoting an electron to an unfilled level, where it can move readily.
The conduction and valence bands in the conductors merge with each other. Hence, the energy gap between the conduction band and the valence band is zero. Thus, the electrons can flow easily under an applied electric field. Hence, metal shows high conductivity.