Question

A substance containing one band completely filled with electrons and other band completely empty, but with a possibility of the empty band becoming populated, behaves as a _________

(a) metal

(b) non-metal

(c) semiconductor

(d) metal and non-metal

I got this question by my college director while I was bunking the class.

This intriguing question originated from Solid State Electrical Properties topic in section Solid State of Chemistry – Class 12

Answer 1

The correct option is (c) semiconductor

Easy explanation: Semiconductors have completely filled valence bands and completely empty conduction bands. The energy gap between the two bands is relatively small and can be overcome by supplying heat, which excites some electrons to the conduction band, thus allowing the conduction of electricity.