Conductors

While electrons can easily move from one atom to another in a material, it is called a conductor. In general term all of the metals are good conductors, having silver the best and copper at second.

Insulators

A material having atoms in which the electrons tend to stay in their own orbits is called an insulator and it might not conduct electricity easily. Though, the insulators are capable to store or hold electricity better than the conductors. These are also known as dielectric materials.

Semiconductors

Carbon might be considered as semiconductor, which conducting less than the metal conductors but more than the insulators. In the similar group are silicon and germanium which are usually used for transistor and other semiconductor components.