Giant covalent

• What is the chemical composition of sand?

  Silicon dioxide
• What is the molecular geometry of diamond?

  Tetrahedral
• What is the structure of graphite?

  Hexagonal sheets built up in layers
• How are the layers in graphite held together?

  By weak intermolecular forces
• What happens to the layers of graphite?

  They can slide over each other
• How does graphite conduct electricity?

  Through delocalised electrons that are not bonded
• What is one layer of graphite called?

  Graphene
• 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 the allotropes of carbon being considered?

  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 in a lattice
• Why does diamond have a high melting point?

  It requires a lot of energy to break bonds
• Does diamond conduct electricity?

  No, it has no free electrons
• How are the carbon atoms arranged in graphite?

  In hexagons forming flat sheets
• What allows graphite to be relatively soft compared to diamond?

  Weak intermolecular forces between the layers of atoms
• Why does graphite have a high melting point?

  Individual layers are strongly bonded covalently
• What happens to the spare electron in graphite?

  It becomes delocalized and moves freely
• What property of graphite allows it to conduct electricity?

  Presence of delocalized electrons
• What can scientists do with isolated layers of graphene?


  Make structures like spheres and tubes
• What are the key differences between diamond and graphite?

  • Diamond:
  • Each carbon bonded to four others
  • Strong covalent bonds
  • High melting point
  • Does not conduct electricity
  • Graphite:
  • Each carbon bonded to three others
  • Weak forces between layers
  • High melting point
  • Conducts electricity due to delocalized electrons
• What are the structural characteristics of diamond and graphite?

  • Diamond:
  • Regular 3D pattern
  • Giant covalent structure
  • Tetrahedral arrangement
  • Graphite:
  • Hexagonal arrangement
  • Large flat sheets
  • Layers held together weakly