1. Models of the Atom Humans Try Lots Of Ideas

2. A Greek philosopher, Democritus, lived about 2500 years ago. He suggested that matter cannot be divided indefinitely, but must have a smallest entity. He called this smallest entity the ATOM. ATOMA = indivisible

3. Dalton Took Democritus’s theory and added scientific data An element is composed of the same atoms All elements are made out of different atoms Each type of atom has a certain mass, size and chemical behavior

4. J.J. Thompson: Found the Electron Before the discovery of the nucleus. The main part of the atom had a positive charge and then there were negative charges scattered throughout

5. The “Marsden” Experiment Ernest Rutherford

6. Difference between Plum Pudding and the Rutherford Model

7. Neils Bohr

8. Light can excite electrons around atoms and this gives rise to “quantum levels”.

10. Prince Louis' full name is Louis Victor Pierre Raymond duc de Broglie

12. Mendeleev's Periodic Table of 1869 1