Valance electrons are the electrons found in an atom's outermost shell. One can tell if a material is semiconductive, conductive, or nonconductive based on the volatility of its electrons. Using valence electrons, it was categorized as follows:

1.Conductor

2.Semi-conductor

3.Insulator

1.Condutors : An atom is categorized as a conductor if its outermost orbit has fewer than four valence electrons. . Since there are more empty spaces in a conductor, the electrons in the outermost orbit are loosely bound, which allows them to flow freely in the presence of an electric field. Because there is no gap between the valence and conduction bands in a conductor, when an electric field is applied, electrons can jump without any obstacles. As shown in figure

Ex: sodium, magnesium, and aluminum

2.Semi-Conductors: If an atom's outermost orbit has precisely four valence electrons, it is classified as a semi-conductor. By sharing electrons with nearby atoms, valence electrons take part in covalent bonding. This creates a strong network and restricts their movement compared to conductors. Because of this, it is difficult to move the electrons when a voltage is applied; for this reason, an external pulse is needed to excite the electrons, and as Figure illustrates, the energy gap between the conduction band and valance bond is more, or equivalent to 1 eV.

Ex: germanium, silicon, and carbon

3.insulators: If an atom's outermost orbit contains more than four valence electrons, it is classified as an insulator. Its electrons are also tightly bound, meaning that they cannot move freely when a voltage is applied, and due to the energy gap between the valence and conduction bands being greater than five eV, it prevents the electrons from moving to the conduction band.

Ex:Germanium, Silicon and carbon