Materials conduct electricity because they have free electrons. Free electrons are electrons that are not bound to a particular atom. They are able to move freely through the material, carrying electrical current.
The number of free electrons in a material determines how well it conducts electricity. Materials with a lot of free electrons, such as metals, are good conductors of electricity. Materials with few free electrons, such as insulators, are poor conductors of electricity.
The way that the atoms in a material are arranged also affects its conductivity. Materials with a regular atomic structure, such as metals, are better conductors of electricity than materials with an irregular atomic structure, such as insulators.
Here are some examples of materials that conduct electricity:
- Metals: Metals are the best conductors of electricity. They have a lot of free electrons that are able to move freely through the material.
- Graphite: Graphite is a form of carbon that has a layered structure. The layers are made up of carbon atoms arranged in a hexagonal lattice. The electrons in the carbon atoms are free to move within the layers, making graphite a good conductor of electricity.
- Solutions of ionic compounds: Solutions of ionic compounds are also good conductors of electricity. The ions in the solution are free to move, carrying electrical current.
Here are some examples of materials that do not conduct electricity:
- Insulators: Insulators are materials that do not have free electrons. They are poor conductors of electricity.
- Wood: Wood is an insulator. The atoms in wood are arranged in a irregular structure, which makes it difficult for electrons to move through the material.
- Plastic: Plastic is an insulator. It is made up of molecules that do not have free electrons.
- Air: Air is an insulator. It is made up of molecules that do not have free electrons.