Atomic structure

• the development of the model of the atom:

  • Dalton - solid sphere
  • Thomson - plum pudding model
  • Rutherford - alpha particle experiment
  • Rutherford - nuclear model
  • Bohr - bohr model
  • Rutherford - the proton
  • Chadwick - the neutron
• in what order where the subatomic particles discovered?

  1. electron
  2. proton
  3. neutron
• explain the alpha particle experiment

  1. scientist fired small, positively charged particles at a piece of gold foil
  2. they expected the alpha particles to travel straight through the gold
  3. some of the alpha particles bounced back and many where deflected (alpha scattering) but most passed through
  4. scientist suggested that the positive charge and the mass on an atom must be concentrated in a small space at its centre - nucleus
• ways to seperate mixtures:

  • filtration - insoluble solid and a liquid
  • crystallisation - soluble solid from a solution
  • distillation - solvent from a solution
  • fractional distillation - two liquids with similar boiling points
  • chromatography - separate a mixture
• proton: relative charge + relative mass

  • RC - +1
  • RM - 1
• neutron: relative charge + relative mass

  • RC - 0
  • RM - 1
• electron: relative charge + relative mass

  • RC - -1
  • RM - 0
• what is an isotope?

  atoms of the same element but with a different number of neutron
• how to calculate relative atomic mass:

  (abundance of isotope 1 x mass of isotope 1)

  +

  (abundance of isotope 2 x mass of isotope 2)

  then /100
• what is an atom?

  are the smallest part of an element that can exits

  • they make up all substances
• what is a compound?

  contains two or more elements chemically combined
• what is a mixture?

  consists of two or more elements or compounds not chemically combined together