What is the common characteristic of metals with regard to heat and electricity?

Metals are known for being good conductors of heat and electricity, which means they are poor insulators. This characteristic arises from their atomic structure; metals have free electrons that can move easily through the material. This mobility allows metals to efficiently transfer energy in the form of heat and electrical current.

When heat is applied to a metal, the energetic vibrations of the atoms are quickly transferred through the lattice by the free electrons, leading to effective heat conduction. Similarly, when an electric voltage is applied, the free electrons flow in response, allowing the metal to conduct electricity well.

The other options do not accurately describe the behavior of metals. While metals can oxidize (especially when exposed to moisture and air), not all metals easily oxidize, making that option less characteristic of metals as a group. Saying metals are good insulators contradicts their well-known conductive properties. Lastly, the statement that metals never conduct electricity is entirely incorrect, as a defining feature of metals is their ability to conduct electricity.

Thus, the characteristic that metals are poor insulators aligns precisely with their behavior as good conductors of both heat and electricity.