bonding

Cards (17)

  • properties of graphite:
    • delocalised electron per atom so can conduct electricity and heat
    • each carbon has 3 bonds, hexagonally bonded
    • weak intermolecular forces between layers but no covalent bonds it is soft and slippery
    • many strong covalent bonds which require lots of energy to overcome so has high melting and boiling points
  • properties of diamond:
    • each carbon has 4 bonds so no delocalised electrons so does not conduct electricity
    • many covalent bonds which take a lot of energy to overcome so have a high melting and boiling point
    • very hard
  • uses of carbon fullerenes:
    • lubricants
    • to deliver drugs to parts of the body
    • catalysts
    • reinforcing materials like tennis rackets (nanotubes)
    • nanotechnology
  • Properties of ionic compounds:
    • giant ionic lattices have strong electrostatic forces of attraction in all directions between oppositely charged electrons
    • high melting and boiling points
    • conduct electricity when melted or dissolved in water
  • Why do ionic compounds only conduct electricity dissolved in water or melted?
    The ions become free to move and carry current throughout the layers of the compound.
  • properties of small molecules:
    • gases or liquids with low melting and boiling points
    • weak intermolecular forces which are broken during melting
    • dont conduct electricity as they don’t have an overall charge
  • properties of metals:
    • giant structures of atoms with strong metallic bonding
    • most have high melting and boiling points
    • layers of atoms are able to slide over eachother so are malleable
  • properties of alloys:
    • made from 2 or more different types of metals
    • different sized atoms distort layers making it harder for them to slide over each other
    • harder than pure metals
  • chemical bonds:
    1. ionic
    2. covalent
    3. metallic
  • metallic bonding consists of positive ions and delocalised electrons arranged in a regular pattern.
  • in metallic bonding, delocalised electrons consist of the electrons lost from the now positive ions.
  • polymers are large covalent bonded chains
  • nano particles are 1nm-100nm in size
  • nanoparticles have a high surface area to volume ratio and therefore make good catalysts
  • nanoparticles can be used in suncream and deodorants without leaving white marks
  • nano particles have different properties to the bulk chemical due to high surface area to volume ratio
  • nanoparticles allow smaller quantities of a material to be more effective than materials with larger particle sizes