Electric charge

2.20 identify common materials which are electrical conductors or insulators, including metals and plastics

Any metal is a conductor of electricity. Any non-metal is an insulator, apart from graphite due to its unusual  structure. (Graphite has delocalised electrons between its layers, these electrons were not used up in covalent bonding and are free to move to carry charge, hence graphite has the unusual property of being able to conduct electricity.)

Copper wires are common, as copper is a very good electrical conductor. PVC is now often used to insulate wires-Polyvinyl chloride. In IGCSE Chemistry, you might know this as poly(chloroethene), a polymer. PVC is cheap to make and flexible, so it now replaces rubber in insulating wires. Because as rubber grew old, it would crack and it would be dangerous if you touched the live wire. Insulation can become unsafe if it is damaged or wet because water can conduct electricity.

SS 2.21 recall that insulating materials can be charged by friction


SS 2.22 explain that positive and negative electrostatic charges are produced on materials by the loss and gain of electrons


SS 2.23 recall that there are forces of attraction between unlike charges and forces of repulsion between like charges


SS 2.24 explain electrostatic phenomena in terms of the movement of electrons


SS 2.25 recall the potential dangers of electrostatic charges, e.g when fuelling aircraft and tankers


SS 2.26 recall some uses of electrostatic charges, e.g. in photocopiers and inkjet printers