What is a free electron? Explain conducting and nonconducting materials in terms of it.

Explanation

In an atom, the electrons move around the nucleus whereas the protons remain bounded in the nucleus. In the atoms of metallic materials, the attractive force prevailing between the valence electrons (negative electric charge) and the nucleus (positive electric charge) is comparatively very small.
During the formation of metallic materials, these electrons get separated from their parent atoms and move in a random manner in the conductor. Such electrons are known as .Free electrons..
These (free) electrons are free to move within the material, but they cannot leave the material. This is because they do not have enough energy to do so.
These free electrons are responsible for the conduction of electric current. Electric current can flow very easily through those materials which contain a large number of free electrons. So they are called conductors. e.g., Metals such as copper, silver and aluminium are called conducting materials.
The materials, which do not contain free electrons and hence do not conduct electric charges are called insulators. e.g., Rubber glass, plastic and leather are insulators.