write note on free electron theory

Classical free electron theory is modeled by drude - Lorentz to explian elctrical conductivity in metals. According to this free electron in a metal (valence electron) move randdomly at room temperature and these free electron are drifted in opposite to the direection of the applied electric field. This is repsonsible for the conduction. Here all the free elctron are are considered as equal in all aspect.

Electrons in metals are delocalized and in a free movement.

free electron model not take into account the potential neither the electron interaction. nearly free electron take into account the potential.J.C. Aguiar

Classical free electron theory could not explain many physical properties. In 1928, Sommerfeld developed a new theory applying quantum mechanical concepts and Fermi-Dirac statistics to the free electrons in the metal. This theory is called quantum free electron theory.