allotropes

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


  Diamond and graphite
• What is an allotrope?


  Different structural forms of the same element in the same physical state
• In what physical state does carbon exist as allotropes?


  Solid state
• What type of structures are diamond and graphite classified as?


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

  Each carbon atom is covalently bonded to four other carbon atoms in a regular 3D pattern
• Why is diamond considered very strong?


  Because it has strong covalent bonds that require a lot of energy to break
• 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 layers in graphite are held together weakly and can slide over one another
• 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 due to covalent bonds
  • High melting point
  • Does not conduct electricity
  • Graphite:
  • Soft due to weak interlayer forces
  • High melting point
  • Conducts electricity due to delocalized electrons
• Compare the bonding and structure of diamond and graphite.

  • Diamond:
  • Each carbon bonded to four others
  • 3D lattice structure
  • Graphite:
  • Each carbon bonded to three others
  • Hexagonal layers that can slide over each other