Why is plastic a poor conductor?

A. They are non-reactive

B. They can melt

C. They have high number of free electron

D. They do not have free electron

Plastic is considered a poor conductor of electricity primarily because of its molecular structure, which lacks free electrons. The correct answer to your question is D: They do not have free electrons. Let’s delve deeper into why this is the case and how it relates to the properties of materials.

The Role of Electrons in Conductivity

To understand why plastics are poor conductors, we first need to look at how electrical conductivity works. Conductivity in materials is largely determined by the presence of free electrons, which are electrons that can move freely within the material. Metals, for instance, have a high number of free electrons, allowing them to conduct electricity efficiently.

Why Plastics Lack Free Electrons

Plastics are made up of long chains of molecules known as polymers. These polymers are typically composed of carbon and hydrogen atoms, which are bonded together in such a way that they do not allow for the presence of free electrons. In simpler terms, the electrons in plastic are tightly bound to their respective atoms and do not have the freedom to move around. This is a key reason why plastics are insulators rather than conductors.

• Non-Reactive Nature: While plastics are often non-reactive, this characteristic does not directly contribute to their conductivity. It simply means they do not easily participate in chemical reactions.
• Melting Point: The fact that plastics can melt is related to their thermal properties rather than their electrical conductivity.
• High Number of Free Electrons: This is true for metals, not plastics. The absence of free electrons is what makes plastics poor conductors.

Comparing Conductors and Insulators

To further illustrate this point, let’s compare plastics with metals. Metals like copper and aluminum have a crystalline structure that allows electrons to move freely. This is why they are excellent conductors of electricity. In contrast, the amorphous structure of plastics prevents the movement of electrons, making them effective insulators.

Applications of Plastic as an Insulator

The insulating properties of plastics are actually beneficial in many applications. For example, electrical wires are often coated with plastic to prevent accidental electrical shocks. This property is harnessed in various industries, from electronics to construction, where safety and efficiency are paramount.

In summary, the reason plastics are poor conductors of electricity is due to their lack of free electrons. This characteristic makes them valuable as insulators in a wide range of applications, ensuring safety and functionality in electrical systems.