Topic 1

• Solvent


  A liquid in which a substance can dissolve (e.g. water)
• Fractional distillation


  1. Heat is applied

  2. Liquid with lowest boiling point evaporates and condenses in beaker

  3. Temperature is altered to repeat process for second liquid

  4. Three liquids are separated based on different boiling points
• First atomic theory: Democritus


  • 500 BC
• Democritus' atomic theory


  • Small spheres
  • Separated from each other by empty space
  • Smallest possible unit of matter
• John Dalton's atomic theory


  1800s
• John Dalton's atomic theory


  • Solid spheres
  • Different types of spheres make up different elements
• J.J. Thomson's plum pudding model


  1897
• J.J. Thomson's plum pudding model

  • Ball of positive charge
  • Electrons mixed throughout it
• Rutherford's nuclear model


  1909
• Rutherford's nuclear model


  • Fired alpha particles at gold sheet
  • Most passed through but some were deflected
  • Dense region of positive charge at centre of atom
• Bohr's electron shell model

  1913
• Bohr's electron shell model


  • Electrons orbit the nucleus in shells
• • Rutherford discovers protons
  • Chadwick discovers neutrons


  20th Century
• Period


  A row in the periodic table
• Group


  A column in the periodic table
• Group I metals (Alkali metals)


  • Contain one electron in their outer shell
  • Reactive and soft
  • Melting and boiling points decrease and reactivity increases down the group
• Alkali metals react with water

  Produce metal hydroxide and hydrogen
• Halogen displacement reaction colour changes

  > Halide salts are colourless

  > Bromine water is orange

  > Chlorine water is colourless

  > Iodine water is brown
• Halide salts (e.g. HCl, KBr, KI) are colourless
• Halogens at room temperature

  • Fluorine - poisonous yellow gas, most reactive
  • Chlorine - green gas
  • Bromine - poisonous, volatile, red-brown liquid
  • Iodine - grey solid