Atomic structure and the periodic table

• Atom


  Basic unit of matter
• Proton charge


  positive/ +1
• Neutron charge


  neutral/ 0
• Electron charge


  negative/ -1
• What makes up the nucleus of an atom

  Protons

  Neutrons
• Which particle determines what element an atom is

  Proton
• Proton relative mass


  1
• Neutron relative mass


  1
• Electron relative mass


  0/ almost 0/ negligible
• Ion


  An atom with a positive or negative charge
• What do electrons orbit the nucleus in

  Energy shells
• Element


  A pure substance made of only one kind of atom
• Atomic number


  The number of protons in the nucleus of an atom
• Mass number


  The total number of protons and neutrons in a nucleus
• Isotopes


  Atoms with the same number of protons, but different numbers of neutrons
• Relative atomic mass


  The weighted mean mass of an atom of an element compared with one-twelfth of the mass of an atom of carbon-12.
• Relative atomic mass formula

  Sum of (isotope abundance x isotope mass number) / 100
• Molecule


  Two or more atoms held together by covalent bonds
• Mixture


  Two or more substances or compounds that are not chemically combined.
• Soluble


  Solid substances that can dissolve in liquids
• Insoluble


  Solids that cannot dissolve
• Solution


  A mixture that forms when one substance dissolves another.
• Solute


  A substance that is dissolved in a solution
• Solvent


  The substance that the solute dissolves in
• Filtration


  Separating insoluble solids from liquids
• Example of filtration


  sand and water
• Filtration process


  We begin with an insoluble solid and a liquid. Let's take a mixture of salt, sand and water. Salt dissolves in water, however the sand does not.

  Pour the mixture into the filter funnel. When you pour the mixture into a filter funnel lined with filter paper, the sand will be caught by the filter paper and the water with salt dissolved will drip through.

  The separation is complete. The liquid (salt solution) and solid (sand) are separated.
• Evaporation process


  1. Put solution in an evaporating dish or crucible

  2. Heat using a bunsen burner

  3. The solution gets more concentrated and crystals form as the solvent dissapears
• Example of crystallisation


  Salt crystals can be obtained from a solution of salty water
• Crystallisation


  The formation of crystals as solvent evaporates from solution
• Crystallisation process


  1) Pour the solution into an evaporating dishand gently heat the solution using a bunsen burner. The water will evaporate and the solution will be more concentrated.

  2) The solution will start to crystallise and turn off the bunsen burner.

  3) Leave the solution to cool.

  4) Leave the crystals todryor put inside an oven.
• Simple distillation


  Used to obtain a solvent from a solution
• Example of simple distillation

  Pure water from sea water - water evaporates until only salt is left in the flask
• Simple distillation process


  1. A solution is heated, usually using a Bunsen burner.

  2. The liquid in the mixture evaporates into a gas.

  3. The gas is cooled by a water jacket, and condenses into a liquid, which then flows into the beaker.
• Fractional distillation


  Method to separate a liquid mixture into its individual components
• Example of fractional distillation


  Crude oil separation or separating ethanol and water.
• Fractional distillation process


  1) Crude oil is heated to a gas - this then enters a fractionating column

  2) The gas is heated and the different-length hydrocarbons condense back into liquids at different points, depending on their boiling point

  3) When they condense, they then drain out of the column
• Chromatography


  A technique that is used to separate the components of a mixture based on the tendency of each component to travel or be drawn across the surface of another material.
• Example of chromatography


  The different colours added to a fizzy drink can be separated by chromatography
• Chromatography process


  1) Components in mixtureseparate outas themobile phasemoves over to thestationary phase.

  2) Each of the chemicals in a mixture will spenddifferentamounts of timesdissolved inthemobile phaseandstuck tothestationary phase.

  3) They all end up indifferent placesin thestationary phase.