The bands which contain zero Kelvin are called valance electrons. The bands with higher energies are called conduction bands.

Conduction band:-The conduction band is the band of the electron orbitals. When the electrons get excited, they jump up toward the conduction band. And the electrons in these orbitals have enough Energy to move freely in the material.

Valance band:-The valance band is the band in which electrons are normally present at absolute zero temperature. The electron present in that state is valance electrons.