Metals are good conductors of electric current for which of the following reasons?

• A. They have free electrons that can move easily throughout the lattice.
• B. They contain only positive ions that carry electric current.
• C. They have a high resistance to the flow of electric charge.
• D. Their atoms are tightly bound and do not allow any movement of charge.

Answer: (A)

Verified step by step guidance

1. Understand that electric current in metals is the flow of electric charge, which is primarily carried by electrons.
2. Recall that metals have a crystalline lattice structure composed of positive metal ions surrounded by a 'sea' of free electrons.
3. Recognize that these free electrons are not bound to any particular atom and can move easily throughout the metal lattice when an electric field is applied.
4. Contrast this with other materials where electrons are tightly bound to atoms and cannot move freely, resulting in poor conductivity.
5. Conclude that the presence of free, mobile electrons in metals is the key reason why metals are good conductors of electric current.