Chemistry Paper 1 - Development of the Atom Model

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Famous alpha particle scattering experiments
- Firing positively charged alpha particles at a thin sheet of gold
- 3. Ernest Rutherford
  - Thought that there must have been a nucleus
    - First nuclear model
  - Development of the Atom Model
    - 2. JJ Thomson
      - From his experiment he said atoms weren't solid spheres
      - Measurements showed that the atom must contain smaller negatively charged particles (Electrons)
      - The solid sphere theory changed and now was known as the plum pudding model
        Ball of positive charge with electrons stuck in it
    - 1. John Dalton
      - Described atoms as solid spheres
      - Different spheres where made out of different elements
    - 5. James Chadwick
    - 4. Niels Bohr
      - Bohr said that the electrons orbit the nucleus in fixed shells
        Each shell is a fixed distances
      - Supported by many experiments
    - 20 years later Chadwick carried out an experiment which had proof for neutral particles
      - Neutrons
  - Most of them deflected
Bohr said that the electrons orbit the nucleus in fixed shells
- Each shell is a fixed distances