chemistry

• what is a covalent bond

  shared pair of electrons between 2 atoms
• structure and properties of a simple covalent

  -doesnt conduct, small molecules, low melting point and boilig points
• structure and properties of giant covalent structure

  solids bonded in a giant lattice, dont normally conduct, high melting point and boiling point
• what are alloys

  mixture of different metals, sizes distort layers so they cant slide over each other
• properties of metals

  high melting points and boiling points, good conductors, malleable
• properties of nanotubes

  high length to diameter ratio, conducts, high tensile strength
• how are ionic compounds held togther

  giant lattice, electrostatic attraction
• allotropes of carbon

  diamond, graphite, graphene, nanotubes, fullerenes
• ionic bonding

  electrostatic attraction between positive and negative ions
• properties of ionic substances

  high melting points and boiling points, conduct in molten but not solid
• uses of nanoparticles

  drug delivery, suncreams
• metallic bonding

  forces of attraction between delocalised electrons and the nuclei of a metal ion
• properties of graphite

  3 covalent bonds, high melting points, conduct, layers slide
• properties of diamond

  high melting point, doesnt conduct
• what are the halogens

  coloured vapours
• what state do the halogens come in

  diatomic