Polymers and Giant Covalent Structures

• Polymers

  • Small units are linked together to form a long molecule that has repeating sections
  • joined by strong covalent bonds
  • Molecular formula - write down the molecular formula of the repeating unit in brackets and put a ‘n’ on the outside
  • forces are larger than simple covalent molecules therefore they need more energy to break them
  • solid at room temperature
  • intermolecular forces are weaker than ionic and covalent bonds so they have a lower boiling point
• macromolecules

  • All the Atoms are bonded to each other by strong covalent bonds
  • high melting and boiling points
  • don’t contain charged particles
  • do not conduct electricity
• Giant Covalent Structures: Diamond

  • each carbon atom forms four covalent bonds in a very rigid giant covalent structure
• Giant Covalent Structures: Graphite

  • each carbon atom forms three covalent bonds to create layers of hexagons
  • each carbon atom also has one delocalised (free) electron
• Giant Covalent Structures: Silicon Dioxide

  • sometimes called Silica - this is what sand is made of
  • each grain of sand is one giant structure of silicon and oxygen