Structure and bonding

Cards (72)

  • Structure of graphite
    1. Each carbon atom forms covalent bonds to three other carbon atoms
    2. Carbon atoms form hexagonal rings arranged into layers with no covalent bonds between the layers
  • Properties of graphite
    • Soft and slippery
    • High melting and boiling point
    • Good conductor of both electricity and heat
  • Graphite is soft and slippery because
    The layers can slide over each other due to no covalent bonds between them
  • Graphite has a high melting and boiling point because

    Breaking the covalent bonds in graphite requires a great deal of energy
  • Graphite is a good conductor of electricity and heat because
    Carbon atoms in graphite have delocalized electrons that can move, allowing for conductivity
  • Diamond is a giant covalent molecule formed from carbon with each carbon atom forming covalent bonds to four other carbon atoms
  • Diamond has a high melting and boiling point due to a large number of strong covalent bonds
  • Diamond cannot conduct electricity because all outer electrons are in covalent bonds with no free electrons
  • Graphite is also a giant covalent molecule formed from carbon with each carbon atom forming covalent bonds to three other carbon atoms
  • Graphite is used as a lubricant in machines to reduce friction between moving parts
  • Graphite contains delocalized electrons that allow it to conduct both electricity and heat
  • Structure of giant covalent molecules
    Describe the structure of diamond and silicon dioxide
  • Properties of giant covalent molecules
    Describe the properties of diamond and silicon dioxide
  • Linking properties to structures
    Link the properties to the structures of the molecules
  • Small covalent molecules have a small number of covalent bonds
  • Small covalent substances have weak intermolecular forces between the molecules
  • When melting or boiling a small covalent substance, weak intermolecular forces need to be broken
  • Breaking weak intermolecular forces in small covalent substances does not take a lot of energy
  • Small covalent substances have low melting and boiling points
  • Most small covalent substances are gases at room temperature
  • Giant covalent substances contain millions of covalent bonds
  • Giant covalent substances
    • Diamond
    • Silicon dioxide or silica
    • Graphite
  • Giant covalent substances are always solids at room temperature
  • All giant covalent substances have high melting and boiling points
  • Melting or boiling giant covalent substances requires breaking all covalent bonds, which takes a great deal of energy
  • Diamond is formed from the element carbon
  • Carbon atom
    Has four electrons in its outer energy level
  • Diamond structure
    Each carbon atom forms covalent bonds to four other carbon atoms
  • Diamond contains a huge number of carbon atoms joined by covalent bonds
  • Diamond is an extremely hard substance
  • Melting point of diamond is over 3,700 degrees Celsius
  • Diamond cannot conduct electricity
  • In diamond, all outer electrons are in covalent bonds, so there are no free electrons to carry electrical charge
  • Silicon dioxide or silica contains the elements silicon and oxygen covalently bonded together
  • Silicon dioxide has a very high melting and boiling point
  • Silicon dioxide has a huge number of strong covalent bonds
  • In order to melt silicon dioxide, the covalent bonds must be broken, requiring a great deal of energy
  • What ratio do nanoparticles have?
    Large surface area to volume ratio
  • What size are nanoparticles?
    Between 1nm- 100nm
  • Surface area to volume ratio?
    surface area / volume