What is the difference between conductors and insulators?
The substances through which electricity can pass are known as conductors. The substances through which electricity cannot pass are known as insulators. There are no free electrons and ions present in the insulator, so they do not conduct electricity. According to energy band theory in conductors the valence band and conductor band are overlapped, so electrons from valence shell easily jump to conductance shell. In this way conductors conduct electricity. In insulators there is a large forbidden band present between valence band and conduction band, so insulators do not conduct electricity.
