Question

Why are metals good conductors of heat and electricity? Why does the ability of a metal to conduct electricity decrease with increasing temperature?

Short answer

Metals are good conductors of heat and electricity due to their structure which has free-moving electrons that can carry energy rapidly across the material. However, as temperature increases, metal atoms vibrate more, disrupting the flow of these electrons, thereby reducing the metal's ability to conduct electricity.

Step-by-step solution

Explaining Metal Conductivity

Metals are good conductors of heat and electricity due to their unique atomic structure. In metal atoms, electrons are loosely attached and can easily move. The outermost shell of a metal atom does not have a full complement of electrons, leaving 'free electrons' that are not tied to any particular atom. These free electrons act as charge carriers, moving energy rapidly from one part of the metal to another. When a voltage is applied (in the case of electricity) or when heat is applied, these free electrons can move quickly through the metal, conducting the electricity or heat.

The Effect of Increasing Temperature on Metal Conductivity

As temperature increases, the atoms in the metal start to vibrate more. This causes more scattering of the free electrons as these electrons encounter the vibrating metal atoms while they move through the metal. The vibration of the atoms with the increase in temperature acts as a disruption to the easy flow of electrons, hence, the resistance to electrical flow (or conductivity) increases. This means that the ability of a metal to conduct electricity decreases with an increase in temperature.