2.7 Diamond & Graphite

• What are the two allotropes of carbon discussed in today's video?

  Diamond and graphite
• What is an allotrope?

  Allotropes are different structural forms of the same element in the same physical state
• In what physical state can carbon take different allotropes?

  Solid state
• What type of structure do both diamond and graphite have?

  Giant covalent structures
• How are the atoms arranged in diamond?

  Each carbon atom is covalently bonded to four other carbon atoms
• Why is diamond very strong and has a high melting point?

  Because it has a regular 3D pattern of strong covalent bonds
• Why doesn't diamond conduct electricity?

  Because it has no free electrons or ions that can move around
• How does the bonding in graphite differ from that in diamond?

  Each carbon in graphite is bonded to only three other carbon atoms
• What is the arrangement of atoms in graphite?

  The atoms are arranged into hexagons that form large flat sheets
• Why is graphite relatively soft compared to diamond?

  Because the individual layers are only held together weakly
• What allows graphite to conduct electricity and heat?

  The presence of delocalized electrons that are free to move around
• What is a single layer of graphite called?

  Graphene
• What can scientists do with isolated layers of graphene?

  They can use them to make other structures such as spheres and tubes
• What are the key properties of diamond and graphite?

  Diamond:

  • Strong covalent bonds
  • High melting point
  • Does not conduct electricity

  
  

  Graphite:

  • Weaker interlayer bonds
  • High melting point
  • Conducts electricity due to delocalized electrons
• How do the structures of diamond and graphite differ?

  Diamond:

  • 3D structure
  • Each carbon bonded to four others

  
  

  Graphite:

  • 2D layers of hexagons
  • Each carbon bonded to three others