Structure and bonding

• States of matter


  • Solids
  • Liquids
  • Gases
• Particles in a solid

  • Packed closely together and vibrate around a fixed point
• Particles in a liquid

  • Close together but can slip and slide over each other in random motions
• Particles in a gas

  • Lots of space between them and zoom around randomly
• When a substance melts or boils


  Energy is transferred to the surrounds from the substance
• When a substance freezes or condenses

  Energy is transferred from the surrounds to the substance
• The particle model has limitations as atoms, molecules or ions are not solid spheres with no forces between them
• What occurs when lithium bonds with chlorine

  One electron transferred from lithium to chlorine
• Why atoms transfer electrons in ionic bonding

  So that they can have full outer shells, to make them stable
• What occurs when lithium bonds with fluorine

  One electron transferred from lithium to fluorine
• What occurs when magnesium bonds with oxygen

  Two electrons transferred from magnesium to oxygen
• What occurs when beryllium bonds with oxygen

  Two electrons transferred from beryllium to oxygen
• What occurs when magnesium bonds with chlorine

  One electron transferred from magnesium to two different chlorine atoms
• What occurs when sodium bonds with oxygen

  Two electrons transferred to an oxygen atom from two different sodium atoms
• Why sodium ions and chlorine ions form an ionic bond

  There is an electrostatic force of attraction between oppositely charged ions
• Sulphur ions and oxygen ions don't form ionic bonds with each other
• Giant ionic lattice


  A huge 3D network of ions
• Ionic substances


  • High melting points
• NaCl(s) does not conduct electricity
• NaCl(aq) conducts electricity
• NaCl(l) conducts electricity
• Soluble


  Dissolves in water
• Insoluble


  Does not dissolve in water
• What needs to be done to magnesium carbonate before it will conduct electricity

  Melt it
• The easiest way for sodium fluoride to conduct electricity

  Dissolve it in water because this does not require high temperatures
• Structure of diamond, graphite and silicon dioxide

  Giant covalent
• Bonds in diamond


  • 4 bonds per carbon
• Graphene


  One layer of graphite
• Fullerene


  Substance made of carbon atoms arranged in a cage
• Methane and water


  Simple molecular (or simple molecules)
• Molecule


  A group of atoms chemically bonded together
• Structure of simple covalent molecules


  • Strong covalent bonds between atoms, weak forces holding the molecules together
• Intermolecular forces


  Weak forces between molecules which hold them together
• Polymer


  Millions of small molecules joined together in a chain to form a large molecule
• Structure of metals


  • Positive metal ions arranged in layers with delocalised electrons
• Alloy


  A mixture of two or more elements, at least one of which is a metal
• Nanoscience


  The study of small particles that are between 1 and 100 nanometers in size
• Applications of nanoparticles


  • Self cleaning glass; titanium oxide and zinc oxide nanoparticles used in suncream; nanoparticles in cosmetics; nanotubes used in nanowires; fullerenes used in medicine
• Risks of nanoparticles