Why Can Metals Conduct Electricity

Metals can conduct electricity because of their unique atomic structure, which allows free electrons to move easily through the material. In a metal, atoms are arranged in a regular lattice, and each atom contributes one or more of its outer electrons to form a shared pool of free-moving electrons, known as a ‘sea of delocalised electrons’. These electrons are not bound to any specific atom, which means they can move freely throughout the metal when a voltage is applied.

This movement of electrons is what allows metals to conduct electricity. When an electric field is introduced, the free electrons drift in the direction of the current, carrying charge from one end of the metal to the other. This ability to conduct electricity is one of the defining physical properties of metals and is consistent across nearly all metallic elements.

The Metallic Bond and Free Electrons

The key to electrical conductivity in metals is the metallic bond. Unlike covalent or ionic bonds, where electrons are shared or transferred between specific atoms, metallic bonding involves a lattice of positively charged metal ions surrounded by delocalised electrons. These electrons move freely within the structure, allowing energy and electrical charge to be transferred quickly and efficiently.

Because these delocalised electrons are already mobile, they respond immediately when an electric field is applied. As a result, metals can conduct electricity without requiring the atoms themselves to move, which also helps explain their ability to conduct heat and resist deformation.

Factors That Influence Conductivity in Metals

Not all metals conduct electricity equally well. The level of conductivity depends on how easily the electrons can move through the metal lattice. For example, silver is the best conductor of electricity, followed closely by copper and gold. These metals have a high number of free electrons and a crystal structure that offers minimal resistance to electron flow.

Temperature also affects conductivity. As metals are heated, the atoms in the lattice vibrate more, which can interfere with the flow of electrons and increase resistance. This is why electrical conductivity in metals tends to decrease with rising temperature, unlike in some other materials such as semiconductors.

Impurities and alloying can also reduce conductivity. For instance, while pure copper is highly conductive, copper alloys like brass or bronze are less so because the presence of other atoms disrupts the regular metal lattice, making it harder for electrons to move freely.

Why Non-Metals Do Not Conduct Electricity

Most non-metals do not conduct electricity because they do not have free-moving electrons. Their electrons are either tightly bound in covalent bonds or occupy full outer shells with no easy way to transfer charge. Materials like plastic, glass, and wood are electrical insulators for this reason.

Some exceptions exist, such as graphite, a form of carbon where each atom has a free electron that can move within a layer. However, this behaviour is unusual for non-metals and arises due to specific structural properties.

Practical Applications of Metal Conductivity

The electrical conductivity of metals is used in countless applications. Copper is widely used in wiring, cables and motor windings due to its excellent conductivity and relative cost-effectiveness. Aluminium, though slightly less conductive, is used in power transmission because it is lighter and cheaper. Silver is the most conductive metal but is too expensive for general wiring, though it is used in specialised electronics.

Gold is also a good conductor and highly resistant to corrosion, which makes it ideal for connectors and contact points in precision devices. Steel and other structural metals may also conduct electricity, though they are used more for strength than electrical performance.

Conclusion

Metals conduct electricity because of the presence of delocalised electrons that are free to move throughout the metal lattice. When a voltage is applied, these electrons carry electric current with ease, making metals ideal materials for electrical wiring, circuits and components. This fundamental property is a direct result of metallic bonding and the unique arrangement of atoms within metal structures.