Final answer:
Metals conduct electricity and heat very well because of their free-flowing electrons in metallic bonding.
Step-by-step explanation:
Metals conduct electricity and heat very well because of their free-flowing electrons. In metallic bonding, the valence electrons are essentially free and are able to move throughout the metallic crystal. These free electrons are not bound to a single atom but can move freely among the atoms, creating a 'sea' of electrons. When an electrical field is applied, these free electrons respond by accelerating, generating thermal energy, and allowing the metal to conduct electricity. This ability to conduct electricity is one of the unique properties of metals.