Topic 2 - C2

• How do metals and non-metals react together?

  ionic bonding
• What happens to electrons in ionic bonding

  transfered
• What structure do ionic compounds form?

  giant ionic lattice
• What are the features of a giant ionic lattice?


  strong electrostatic forces of attraction between oppositely charged ions in all directions of lattice
• Ionic compound properties:

  • high melting/boiling points

  -> high intermolecular forces needed to overcome

  • solid can't conduct electricity

  -> ions are held into place

  -> has to be dissolved in water or melted (molten)
• How do non-metals react together?

  Covalent bonding
• What happens to electrons in covalent bonding?

  shared
• What is an allotrope?


  different structural forms of the same element in the same physical state
• What are the allotropes of carbon?

  Diamond, graphite, graphene, fullerenes
• Diamond:

  • structure

  -> carbon atoms form four covalent bonds, make it really hard

  • melting/boiling point

  -> high due to strong covalent bonds which have to be overcome

  • electricity

  -> cannot conduct

  -> no free electrons or ions
• Graphite properties:

  • structure

  -> carbon atoms form three covalent bonds and an arranged in hexagons

  • strength

  -> no covalent bonds between layers so soft and slippery as they move freely

  • melting/boiling point

  -> covalent bonds in layers need energy to break

  • electricity

  -> one electron (out of four) is delocalised

  -> can conducts electricity and thermal energy
• Graphene properties:

  • structure

  -> sheet of carbon atoms join in hexagon

  • strength

  -> network of covalent bonds makes it strong

  -> also light so used to improve strength to things without adding to much weight

  • electricity

  -> delocalised electrons conduct electricity
• Fullerenes properties:

  • structure

  -> shaped like closed tubes or hollow balls

  -> made up of carbons arranged in pentagons, hexagons or heptagons

  • uses

  -> cage other molecules (deliver drugs)

  -> big surface area (cataylst)

  -> lubricants

  -> form nanotubes
• Nanotube properties:

  • length:diameter high

  • conduct electricity/heat

  • high tensile strength (dont break when streched)

  • used to strengthen materials withiut adding to much weight
• How big are nanoparticles?

  Diameter between 1nm (1×10‐⁹) to 100nm (1×10‐⁷)
• What are nanoparticles used for?

  • nanomedicine

  -> particles are absorbed more easily then most particles so they can deliver drugs right to the cells

  • electric circuits

  -> conduct electricity

  • silver nanoparticles antibacterial properties

  -> added to polymer fibres then used to make surgical masks and wound dressing

  • cosmetics

  -> added to moisturisers without making them oily