Why are metals good conductors of electricity?

Metals are good conductors of electricity because they have free electrons that can move easily, facilitating electric current flow.

In more detail, the atomic structure of metals is the key to their ability to conduct electricity. Metals are made up of a lattice of positive ions surrounded by a 'sea' of delocalised electrons. These electrons are not attached to any particular atom and are free to move throughout the metal structure. This is often referred to as the 'sea of electrons' model.

When a voltage (or a 'push') is applied across a piece of metal, these free electrons can move easily through the metal, carrying the electric charge with them. This movement of charge is what we know as an electric current. The ease with which these electrons can move is what makes metals such good conductors of electricity.

Different metals have different levels of conductivity, depending on the number of free electrons they have available. For example, silver is the best conductor of electricity because it has the most free electrons, but it is expensive and not always practical to use. Copper and aluminium are also very good conductors and are more commonly used due to their availability and lower cost.

It's also worth noting that the conductivity of metals can be affected by factors such as temperature. As the temperature of a metal increases, the ions in the metal lattice vibrate more. This can cause more collisions with the free electrons and impede their flow, reducing the conductivity of the metal.

In summary, the excellent conductivity of metals is due to their atomic structure, specifically the presence of free, delocalised electrons that can move easily when a voltage is applied, carrying electric charge and creating an electric current. The number of these free electrons and external factors like temperature can affect the level of conductivity.