4.2

• Ionic binding 


  Metal and non metal atoms react, transferring ions, metal loses electrons into positive ions and non metal gains electron into negatively charged ions.
• Ions produced by group 1 2 and 6 7 have what structure?

  They have the electronic structure of a noble gas
• Ionic compound


  A giant structure of ions held together by strong electrostatic forces of attraction between oppositely charged ions. Forces act in al directions in lattice.
• Covalent bonding 


  Atoms share pairs of electrons with strong Bonds
• Properties of small molecules

  Atoms have strong covalen bonds but intermolecular forces are weak between molecules so easy to melt or boil
• Metallic bonding 


  Giant structure of atoms in regular pattern, outer shell of metal atoms are delocalised so can move freely giving strong metallic bonds
• How do forces between particles affect boiling and melting 


  Stronger the forces higher the boiling point.
• Limitations of simple Particles model 


  particles aren’t solid or in elastic or spheres and doesn’t show the forces between particles or how strong
• Properties of ionic compounds 


  Giant ionic lattices with strong electrostatic forces between opposite charged ions. Compounds have high melting and boiling points As lots of energy needed to break strong bonds. Conducts electricity when molten or dissolved as ions are free to move so charge csn flow
• Properties of small molecules

  Weak intermolecular forces between molecules, as larger molecules Have higher melting and higher boiling points. Don’t conduct electricity as molecules don’t have overal electric charge
• Polymer 


  Large molecules in which atoms are elinked by strong covalent bonds. With strong im forces so solid at room temperature
• Properties of metals and alloys

  Strong metallic bonding so high melting and boiling points.

  In pure metals, layers of atoms allows metals to be bent and shaped, so mixed with other metals into alloys.

  Alloys are harder as new atoms distorts the layers making it harder to wlide Over each other and bend
• Why are metals good conductors


  Delocalised electrons in the structure can carry electrical charge through the metal, and Good conductor of thermal energy as electrons transfer energy
• diamond structure 


  Each atom forms four strong covalent bonds so very hard, high melting points and can’t conduct electricity.
• Graphite structure and bonding 


  Each carbon atoms forms three strong covalent bonds, so one delocalised carbon electron which can conduct electricity and thermal energy well, and has high melting point(lots energy need3 to break).

  Weak intermolecular forces between layers so can slide so lubricating
• graphene 


  Single layer of graphite in hexagons, so very strong, light, and csn improve strength without inching weight.

  Delocalised electrons allows it to conduct electricity so csn be used in Electronics
• Fullerenes 


  Molecules of carbon atoms in hollow shape in hexagonsl rings. Can be used for nanotech electronics and metals due to high length to diameter ratios.

  Delivery of drugs,catalyst, lubricatiion
• First fullerene discovered

  Buckminsterfullerene.
• Carbon nanotubes


  Cylinders of fullerene. High length to diameter ratio and conducts heat and electricity well. High tensile strength so csn be used in no technology in electronics or strengthening materials without adding weight (tennis rackets)
• What does nano science refer to 


  Structures 1-100nm in size
• finer particles 


  100 to 2500nm
• Coarse marticles 


  1x10^-5 - 2.5^-6 metres
• Nanorparticesk uses 


  Catalysts

  Drug delivery

  Electric circuits

  Cosmetic
• Cons of nanaparticeles 


  Can damage the environment or cells

  impacts on the body haven’t clearlt been studied yet of
• why are nanoparticel properties different 


  Higher surface area to volume ratio
• Why is buckninster fulleren a good lubricant 


  Molecules are ball shaped so will roll
• Why is graphite soft and conducts Electricity 


  Each carbon atoms form three covalent bonds forming layers (of hexagonal rings).

  Layers can slide over each other so soft, and conducts electricity because of delocalised electrons
• Why do carbon nanotubes conduct electricity 


  Has delocalised electrons which allows electrons to move throughout the structure
• Why is nitrogen gas at room temperature 


  Weak intermolecular forces which need little energy to overcome
• why are nano particles cheaper to use then coarse 


  Higher surface area to volume ration so less can be used for same effect
• Limitations of ball and stick


  There are no sticks irl between the atoms