Using the free electron model idea, explain the fundamental difference between electrical conductors and electrical insulators. Give an everyday example of each.
The Correct Answer and Explanation is:
Correct Answer:
The fundamental difference between electrical conductors and electrical insulators, according to the free electron model, lies in the availability and mobility of free electrons. Conductors have many free electrons that can move easily through the material, while insulators lack such free electrons, preventing current flow.
Detailed Explanation (300 words):
The free electron model describes the behavior of electrons in a solid, particularly in metals. In this model, certain electrons—known as conduction electrons—are not bound to individual atoms but are instead free to move throughout the entire solid. These electrons are responsible for the electrical conductivity of materials.
In electrical conductors such as copper, silver, or aluminum, the outermost electrons of atoms are loosely held and can break free to form a “sea” of delocalized electrons. These free electrons move easily in response to an electric field, allowing electric current to pass through the material. The atoms in such materials are arranged in a lattice structure, and the free electrons move through this lattice with minimal resistance. This explains why metals are excellent conductors of electricity.
On the other hand, electrical insulators such as rubber, glass, or plastic have tightly bound electrons. These electrons remain associated with their parent atoms and cannot move freely throughout the material. As a result, when an electric field is applied, there is little to no movement of charge, making it nearly impossible for current to flow. The energy gap between the valence band and the conduction band in insulators is very large, making it difficult for electrons to gain enough energy to move to the conduction band.
An everyday example of a conductor is copper, commonly used in household wiring. It allows electricity to flow efficiently from power sources to appliances. An everyday example of an insulator is the plastic coating around electrical wires, which prevents accidental contact with the conducting metal inside and protects users from electric shock.
