Giant Covalent Structures and Fullerenes

• What are giant covalent structures primarily composed of?

  They are composed of many covalent bonds.
• How do giant covalent structures differ from giant ionic lattices?

  Giant covalent structures do not have any ions.
• What is the term used for giant covalent structures due to their size?

  They are called 'macromolecules.'
• What is the main element that forms giant covalent structures mentioned in the material?

  Carbon.
• Why are diamonds considered ideal for cutting tools?

  Because they are very hard due to their rigid structure.
• What contributes to the high melting point of diamonds?

  The strong covalent bonds require a lot of energy to break.
• Why doesn't diamond conduct electricity?

  Because it has no free electrons or ions.
• What is the appearance of graphite?

  Graphite is black and opaque, but somewhat shiny.
• How does the structure of graphite allow it to be used in pencils?

  The layers of carbon atoms can slide over each other, leaving marks on paper.
• Why is graphite considered a good lubricating material?

  Because the layers can slide over each other easily.
• What allows graphite to conduct electricity?

  The presence of delocalised (free) electrons that can move.
• What is graphene?

  A single sheet of graphite.
• What makes graphene a 'wonder material'?

  Its covalent bonds make it extremely strong and lightweight.
• How does graphene compare to graphite in terms of electrical conductivity?

  Graphene conducts electricity better than graphite.
• What are fullerenes?

  Large carbon molecules shaped like hollow balls or tubes.
• How are the carbon atoms in fullerenes arranged?

  In rings, similar to those in graphite.
• Why do fullerenes conduct electricity?

  Because they have delocalised electrons.
• How do the melting and boiling points of fullerenes compare to those of diamond and graphite?

  They are lower than those of diamond and graphite but still relatively high for molecular substances.
• What are the key properties of diamond?

  • Lustrous and colorless
  • Forms four covalent bonds
  • Very hard due to rigid structure
  • High melting point
  • Does not conduct electricity
• What are the key properties of graphite?

  • Black and opaque, somewhat shiny
  • Forms three covalent bonds
  • Layers can slide over each other
  • High melting point
  • Conducts electricity due to delocalised electrons
• What are the key properties of graphene?

  • Single sheet of graphite
  • Extremely strong and lightweight
  • Transparent
  • Better electrical conductor than graphite
• What are the key properties of fullerenes?

  • Large carbon molecules shaped like hollow balls or tubes
  • Carbon atoms arranged in rings
  • Conduct electricity due to delocalised electrons
  • Melting and boiling points are relatively high for molecular substances