Allotropes of Carbon

• What is an allotrope?


  Different forms of the same element.
• How many covalent bonds does each carbon atom form in a diamond?


  4.
• Due to the covalent structure of diamond, what characteristic does this give it?


  Very hard.
• What is the melting point of diamond like and why?


  High; due to strong covalent bonds.
• Why does diamond not conduct electricity?


  It has no free electrons or ions.
• How many covalent bonds does each carbon atom form in graphite?

  3.
• Why can layers of graphite move over eachother?


  No covalent bonds between layers means they are held together weakly.
• What can graphite be used for?


  Lubricating material.
• What is the melting point of graphite like and why?


  High, due to strong covalent bonds.
• Only 3 out of each 4 of carbons outer electrons are used in bonds, so each carbon has one delocalised electron which means it is free to move so graphite conducts electricity and thermal energy.
• What is graphene?


  A sheet of carbon atoms joined in hexagons.
• Graphene is just one atom thick, making it a two-dimensional shape.
• What can graphene be used for?


  Added to composite materials to improve their strength without adding much weight.
• Why can graphene be used in electronics?

  It contains delocalised electrons which means it can conduct electricity.
• What is a fullerene?


  Molecules of carbon shaped like hollow tubes or carbon balls.
• What was the first fullerene to be discovered?

  Buckminsterfullerene.
• What are fullerenes made out of?

  Carbon atoms arranged in hexagons, but can contain pentagons or heptagons.
• What can fullerenes be used for?


  To cage other molecules, by trapping it inside the structure.
• What is an example of a use of a fullerene?


  Drug delivery into the body.
• Fullerenes can form nanotubes- tiny carbon cylinders.
• The ratio between the length and diameter of nanotubes is very high.
• Nanotubes can conduct both electricity and thermal energy.
• Nanotubes also have a high tensile strength.
• What is technology that uses small particles like nanotubes called?


  Nanotechnology.
• What can nanotubes be used in?


  Electronics or strengthening materials.