The history of the atom

• Plum pudding model


  A model of the atom where the positive charge is spread throughout the atom like plums in a pudding, with the electrons embedded in it
• Rutherford's experiment

  1. Alpha particles fired at gold foil

  2. Most particles passed through

  3. Some particles deflected at different angles

  4. Some particles deflected backwards
• Rutherford's experiment results

  Disproves the plum pudding model
• Rutherford's model of the atom

  • Positively charged nucleus at the centre
  • Negative electrons in a cloud around the nucleus
  • Most of the atom is empty space
• Bohr's nuclear model

  • Electrons in fixed shells around the nucleus
  • Explains many atomic phenomena
• Further experiments showed the existence of protons in the nucleus
• The discovery of neutrons resulted in the modern atomic model
• Some other people's work is constantly being built upon, advancing our understanding of a topic