C2

• Ionic bonding is how metals bond to non metals
• In ionic bonding, metal atoms donate electrons to non-metals to form ions. These opposite + and - charges are strongly attracted by electrostatic forces
• Dot and cross diagrams show the electrons on the outer shell
• Dot and cross diagrams:

  • Square brackets
  • Charges shown

  
• The charges of all ions in an ionic compound must add to 0
• Dot and cross diagrams show the formation of ionic compounds
• Dot and cross diagrams don't show the size or arrangement of ions
• Ionic compounds have a giant ionic lattice structure and strong electrostatic forces of attraction
• Ionic compounds have high melting and boiling points due to strong electrostatic forces of attraction
• Ionic compounds conduct electricity when molten as the ions are free to move
• When molten, ions are free to move when dissolved in water so carry electric charge
• Covalent bonding is 2 non-metal atoms sharing pairs of electrons to make covalent bonds
• Covalent bonds are very strong
• Dot and cross diagrams can be drawn to show covalent bonds
• Each covalent bond provides 1 extra shared electron
• Displayed formula can be used however it doesnt show 3D structures

  
• Ionic compounds are held together by strong electrostatic forces of attraction between oppositely charged ions
• Properties of simple molecular substances:

  • Low melting and boiling points due to the weak intermolecular forces
  • Don't conduct electricity
  • Liquids or gases at room temperature
• Polymers are small units linked together to form a long molecule
• Atoms in a polymer are joined by strong covalent bonds
• Giant covalent structures have high melting and boiling points
• Diamond:

  • Hard as each carbon atom forms 4 covalent bonds
  • High melting point as covalent bonds take a lot of energy to break
  • Doesn't conduct electricity as there are no free electrons
• Graphite:

  • Soft as each carbon atom forms 3 covalent bonds
  • Slippery as there are no bonds between layers
  • High melting point as covalent bonds take a lot of energy to break
  • Conducts heat and electricity as it has 1 delocalised electron
• Graphene:

  • 1 atom thick layer of graphite
  • Strong and light
  • Delocalised electrons can conduct electricity through the structure
• Fullerenes are closed tubes or hollow balls arranged in hexagons
• Fullerenes cage other molecules so can be used to deliver drugs inside the body
• Fullerenes have a large surface area so are good industrial catalysts
• Nanotubes are formed from fullerenes
• Nanotubes conduct heat and electricity and are used in electronics
• Metallic bonding is the strong forces of attraction between positive metal ions and the shared negative electrons
• The forces of attraction in metallic bonding are very strong
• Metals are solid at room temperature due to the electrostatic forces of attraction between the metal atoms and the delocalised sea of electrons
• Metals are good conductors of heat and electricity as delocalised electrons carry charge and heat through the structure
• Alloys are a mix of a metal and another element
• Alloys:

  • Different elements have different sized atoms
  • New metal atoms distort the layers making it difficult to slide over each other
  • Makes alloys harder than pure metals
• Nanoparticles are between 1nm and 100nm in diameter
• Nanoparticles have a large SA:V
• Uses of nanoparticles:

  • Drug delivery
  • Deodorants
  • Moisturisers
• Effects of nanoparticles:

  • Cell damage
  • Environmental damage