Chapter 21, Problem 21.20CP

Interpretation Introduction

Interpretation:

The electron population of energy bands of molecular orbital for given group $\text{4A}$ elements has to be sketched.  Also the electron population changes in group $\text{4A}$ elements has to be explained.

Concept introduction:

Valence band:

Valence band is defined as valence electron orbital of an element.  It is a bunch of orbitals from which electrons shift to conduction band when excitation occurs.  Conduction band and valence band are combined together in conductors.  In semiconductors, there is a small band gap which separates conduction band and valence band.

Conduction band:

It is a bunch of orbitals into which electrons shift from valence band when excitation occurs.  Electrons present in conduction band are free to move which creates electric current.

Band gap:

Band gap is the difference in energy between conduction band and valence band.  In semiconductors, there is a small band gap which separates conduction band and valence band