The table below shows information about three allotropes of carbon: diamond, graphite, and graphene.
| Allotrope | Covalent bonds per carbon atom | Electrical conductivity |
|---|---|---|
| Diamond | ........................ | None |
| Graphite | 3 | High |
| Graphene | 3 | ........................ |
Complete the table to show the covalent bonds per carbon atom in diamond and the electrical conductivity of graphene.
Graphite can conduct electricity. Explain why graphite can conduct electricity. Use ideas about structure and bonding in your answer.
Diamond has a very high melting point. Explain why diamond has a very high melting point. Use ideas about structure and bonding in your answer.
Silicon is in the same group of the Periodic Table as carbon. Silicon dioxide (SiO2\text{SiO}_2SiO2) has a very high melting point, whereas carbon dioxide (CO2\text{CO}_2CO2) is a gas at room temperature. Explain this difference in terms of structure and bonding.