Chemistry

• Plum pudding model


  The atom was a ball of positive charge with negative electrons embedded in it
• Discovery of the electron

  Led to plum pudding model of the atom
• Alpha particle scattering experiment

  • Mass of an atom was concentrated at the centre
  • Nucleus was charged
• Alpha particle scattering experiment


  Replaced the plum pudding model with the nuclear model
• Nuclear model


  Electrons orbit the nucleus at a specific distance
• Protons


  Positive charge of a nucleus could be subdivided into a whole number of smaller particles, each particle having the same amount of positive charge
• Neutrons


  Exist within the nucleus
• James Chadwick


  Provided the evidence to show the existence of neutrons within the nucleus