1. History of Atomic Theory

2. Matter  The things around you that are matter (tables, air, people) consist of different types of atoms.

3. Development of Atomic Theory

4.  John Dalton (born England, 1766)  Revived Democritus’s theory that all matter was composed of tiny particles called ‘atoms’.  Thought that the difference between elements was the size of their atoms. Development of Atomic Theory

6.  JJ Thompson (born England, 1856)  Used cathode ray tube experiments to discover the electron.  Developed the ‘plum pudding’ model. Development of Atomic Theory

8.  Ernest Rutherford (born New Zealand, 1871)  Used gold foil experiment to show that atoms were mostly empty space, with a positively charges nucleus in the centre. Development of Atomic Theory

10.  Niels Bohr (born Denmark, 1885)  Used the emission spectrum of hydrogen as the basis of his theory that electrons existed at different energy levels. Development of Atomic Theory

12.  Erwin Schrodinger (born Germany, 1887)  Used quantum mechanics to describe electrons as waves rather than particles. Development of Atomic Theory