What causes the high electrical conductivity in metals?

The high electrical conductivity in metals is caused by the presence of free-moving, delocalised electrons.

In more detail, 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. This is often referred to as the 'sea of electrons' model.

The outermost electrons in a metal atom are loosely held, which allows them to move freely. These are known as valence electrons. When a voltage (or a push) is applied across a piece of metal, these free electrons move towards the positive terminal, creating an electric current. This movement of electrons is what we refer to as electricity.

The more free electrons a metal has, the better it conducts electricity. For example, silver, copper, and gold are among the best conductors of electricity because they each have one free electron per atom.

In addition, the arrangement of atoms in a metal also contributes to its high electrical conductivity. Metals have a regular, closely packed arrangement of atoms. This allows the electrons to move more easily through the structure, further enhancing the metal's ability to conduct electricity.

The temperature of the metal can also affect its electrical conductivity. As the temperature increases, the metal ions vibrate more. This can disrupt the flow of electrons and decrease the metal's conductivity. However, this effect is generally small unless the metal is heated to a very high temperature.

In summary, the high electrical conductivity in metals is primarily due to the presence of free-moving, delocalised electrons. The number of these electrons, the arrangement of atoms in the metal, and the temperature can all affect a metal's ability to conduct electricity.