If a material has few electrons that can travel freely, it is classified as what?

A material that has few electrons that can travel freely is classified as an insulator. In these materials, the electrons are tightly bound to their respective atoms, which prevents them from moving freely and conducting electricity. This property is crucial in electrical systems where it is necessary to prevent unwanted current flow, ensuring safety and efficiency.

In contrast, conductors have many free electrons, allowing them to easily transport electrical current. Superconductors allow for flow with zero resistance under certain conditions, while resistors are components designed to limit current flow, but they still allow some level of electron movement. The distinct lack of free electron movement in insulators is what fundamentally differentiates them from these other categories of materials.