Answer
The electrical properties of copper and rubber are different because
(b) many electrons are free to move in copper but nearly all are bound to molecules in rubber.
Work Step by Step
In copper, there are many free electrons. When the copper has a potential difference across it, the free electrons flow through the copper, and this is what makes copper a good conductor of electricity.
However, in rubber, most electrons are bound to molecules so the electrons are not free to move. This is why rubber is not a good conductor of electricity.
The electrical properties of copper and rubber are different because
(b) many electrons are free to move in copper but nearly all are bound to molecules in rubber.
