Chemistry C1

• Atoms contain Protons, neutrons and electrons

  • Atoms have a radius of 0.1 nanometres
  • Nucleus contains protons and neutrons
  • The nucleus has a radius of 1 x 10-14 nm
• Electrons:

  • have virtually no weight
  • Negatively charged and ting
• Protons:

  • relative atomic mass is 1
  • Positively charged
• Atomic number and mass number:

  • mass number is on top tells you the number of protons and neutrons
  • Atomic number at the bottom only tells you the number of protons
• Element- substance made up of atoms that all have the same number Of protons in their nucleus
• Isotopes:

  • Same protons
  • different number Of neutrons
• Relative atomic mass:

  sum of (isotope abundance x isotope mass number ) ÷ sum of the abundance of all isotopes
• compounds :

  • formed when two or more elements react together to form a new substance
  • Atoms are in fixed proportions throughout the compound
  • Held together by chemical bonds
  • completely different properties to the origional element
• Mixtures

  • easily separated
  • No chemical bonds
  • can be separated with simple separating techniques
• Chromatography


  1. Draw a line near the bottom of a sheet of filter paper (use a pencil as they are insoluble)

  2. Add the spot of ink to the line and place the sheet into a beaker of solvent e.g. water

  3. The solvent used depends on what is being tested. some compounds dissolve well in water, but sometimes other Solvents like ethanol are needed

  4. Make sure the ink isn't touching the solvent

  5. The solvent will seep up the Paper and carry the ink with it
• Chromatography


  • Each different dye will move up the paper at a different rate so they will separate out
  • If any of the inks are insoluble they'll stay on the baseline
  • When the solvent has reacted the top of the paper take it out to dry and you'll have a chromatagram
• Filtration:

  • filter paper is folded into a cone shape over a conical flask
  • sediment is caught in filter paper
  • can only be used if sediment is insoluble
• Evaporation:

  1. Pour the solution into an evaporation dish
  2. slowly heat the solution. The solvent will evaporate and the solution will become more concentrated. eventually crystals will start to form
  3. keep heating until all you have is dry
• Crystallisation:

  1. Evaporating dish and gently heat the solution. some of the solvent will evaporate, making the solution more concentrated
  2. once some of the solvent has evaporated or you Start to see crystals forming, take it off the heat
  3. place the dish somewhere warm and and dry
• Simple Distillation:

  1. Solution is heated and the part of the solution with the lowest boiling point evaporates first
  2. The vapour is then cooled by the condenser and is collected as a liquid

  • Can be used to separate pure water from seawater
  • Can only separate things with very different boiling points
• Fractional distillation:

  1. Put your mixture in the fask underneath the fractionating column and heat it
  2. The liquid with the lowest boiling points evapo rates
  3. liquids with higher boiling points may also start to evaporate, but the column is cooler at the top So they will only get part of the way up before condensing
• 19th Century: John Dalton - Atoms are solid spheres that cannot be devided into Smaller particles
• 1897: JJ Thompson created the plum pudding model that showed atoms as positively charged balls with electrons stuck in them
• 1909: Ernest Rutherford fired positively charged alpha particles at a thin sheet of gold. It proved the plum pudding model incorrect and so Rutherford created the Nuclear modes
• Niels Bohr discovered that electrons orbit the nucleus in shells
• Metals:

  • Strong but malleable
  • good conductors
  • high melting and boiling points
  • form positive ions when they react
  • sonorous
  • Shiny
• Non metals:

  • dull looking
  • brittle
  • lower density
  • don't conduct