Which molecular-level property of copper makes it an ideal material for use in electrical wiring?

• A. Copper molecules are highly reactive with water.
• B. Copper molecules form strong covalent bonds with oxygen.
• C. Copper atoms have a low atomic mass compared to other metals.
• D. Copper atoms have a high density of free-moving valence electrons.

Answer: (D)

Verified step by step guidance

1. Understand that electrical conductivity in metals depends on the presence of free-moving electrons, often called conduction electrons, which allow electric current to flow easily.
2. Recognize that copper is a metal with atoms arranged in a lattice structure where some valence electrons are not tightly bound to any particular atom and can move freely throughout the metal.
3. Identify that the key molecular-level property making copper ideal for electrical wiring is the high density of these free-moving valence electrons, which facilitates efficient electrical conduction.
4. Note that properties like reactivity with water, covalent bonding with oxygen, or atomic mass are less relevant to electrical conductivity compared to the availability of free electrons.
5. Conclude that copper's excellent electrical conductivity arises from its atomic structure that provides many free valence electrons, making it a preferred material for wiring.