Graphite — AQA GCSE Chemistry
Test yourself on Graphite with AQA GCSE practice questions.
7 days Premium · Then free forever · No card, no charge
Graphite explained
In graphite each carbon atom forms three covalent bonds, using three of its four outer electrons.
Read the full explanation
The remaining outer electron from each carbon atom becomes delocalised. These delocalised electrons are free to move throughout each layer of hexagonal rings, so graphite conducts electricity. The layers themselves are held together by weak intermolecular forces, allowing them to slide. This is why graphite is used for electrodes in electrolysis and in batteries. For example, a graphite rod conducts electricity because the delocalised electrons can carry charge through the structure. The number of delocalised electrons is one per carbon atom, so the ratio of carbon atoms to delocalised electrons is 1:1.
Your focus
- State that one electron per carbon atom is delocalised in graphite.
- Explain how delocalised electrons allow graphite to conduct electricity.
- Relate the bonding in graphite to the number of delocalised electrons.
Graphite exam tips
Marking Points
- States that one electron from each carbon atom is delocalised in graphite.
- Explains that three of the four outer electrons per carbon atom are used in covalent bonding.
- Links delocalised electrons to the ability of graphite to conduct electricity.
- States that delocalised electrons are free to move within the layers.
- Uses the 1:1 ratio of carbon atoms to delocalised electrons correctly.
Examiner Tips
- 💡State the number of delocalised electrons per carbon atom explicitly.
- 💡Link delocalised electrons directly to electrical conductivity in graphite.
- 💡Use the phrase free to move when describing delocalised electrons.
Common Mistakes
- Saying all four electrons per carbon atom are delocalised: correct this by stating only one electron per carbon atom is delocalised.
- Saying graphite conducts because ions move: correct this by stating delocalised electrons carry charge.
- Saying the delocalised electrons are localised between two atoms: correct this by stating they are free to move throughout the layer.