✫allotropes of carbon✫

• What is an 'allotrope'?

  Different structural forms of the same element in the same physical state.
• What are some examples of allotropes of carbon?

  Diamond, graphite, graphene & fullerenes
• State the structure of diamond and graphite.

  They are giant covalent structures/ have a regular lattice of covalently bonded atoms which makes them very strong.
• How is each carbon atom bonded in diamond?

  Each carbon atom is covalently bonded to 4 other carbon atoms.
• What does diamond have?

  A high melting point due to the strong covalent bonds.
• Why can diamond not conduct electricity?

  As it has no free electrons or ions.
• How are the atoms bonded in graphite?

  They are covalently bonded to only three other carbon atoms.
• Describe the structure of graphite.

  The atoms are arranged into hexagons that together, form large flat sheets that are then arranged on top of one another, to form layers.
• Why are the layers held together weakly?

  As there are no covalent bonds between them.
• Why is graphite relatively softer than diamond?

  As the layers held together share no covalent bond, allowing them to slide over one another.
• Does graphite have a high melting point?

  yes, as it still contains strong covalent bonds between each individual layer.
• What allows graphite to conduct heat & electricity?

  The spare delocalised electrons.
• What is a single layer of graphite known as?

  Graphene.
• How can carbon atoms be arranged in?

  Straight chains, branched chains & rings.
• What is silicon dioxide known as?

  Silicon dioxide is known as sand.