Allotropes: diamond and graphite

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

  Diamond and graphite
• What are allotropes?

  Different structural forms of the same element
• In what physical state are carbon allotropes considered in this video?

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

  Giant covalent structures
• What is the arrangement of atoms in diamond?

  Each carbon is bonded to four others
• Why is diamond very strong?

  It has strong covalent bonds requiring high energy to break
• Why doesn't diamond conduct electricity?

  It has no free electrons or ions
• How many carbon atoms does each carbon in graphite bond with?

  Three other carbon atoms
• What is the arrangement of atoms in graphite?

  Hexagons forming large flat sheets
• How are the layers in graphite held together?

  Weakly, with no covalent bonds between them
• What property of graphite allows it to be relatively soft?

  Layers can slide over one another
• Why does graphite have a high melting point?

  Individual layers are strongly held by covalent bonds
• What happens to the spare electron in graphite?

  It becomes delocalized and can move freely
• What do the delocalized electrons in graphite allow it to do?

  Conduct electricity and heat
• What is a single layer of graphite called?

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

  Use them to make other structures
• What are the key differences between diamond and graphite?

  • Diamond:
  • Bonds to four carbon atoms
  • Strong, high melting point
  • Does not conduct electricity
  • Graphite:
  • Bonds to three carbon atoms
  • Soft, layered structure
  • Conducts electricity due to delocalized electrons
• What are the properties of diamond and graphite that relate to their structures?

  • Diamond:
  • Strong covalent bonds
  • Regular 3D pattern
  • High melting point
  • Graphite:
  • Weak interlayer forces
  • Delocalized electrons
  • High melting point but softer
• What are the allotropes of carbon mentioned in the video?

  • Diamond
  • Graphite
  • Graphene (single layer)
  • Fullerenes (to be discussed later)