1. Scientists The atom

2. Democritus - 400 BC- Greek philosopher - No experimenting -Matter made up of indivisible particles = “atomos”

3. 1. Matter made up small particles= atoms Cant be created, destroyed, or made smaller 2. Atoms of same element are identical Different elements = different atoms 3. Chem. Rxn  atoms separate, join, or rearrange 4. Atoms of different elements can combine: compounds. Dalton (1802 ish)

4. 1904-J.J. Thomson Plum Pudding Model/ Chocolate Chip Cookie Discovered electrons ( 1897)

5. Thomson versus Rutherford

6. Rutherford’s Goldfoil Experiment

7. 1911-Rutherford Discovered atom to have: – mostly empty space – dense + charged center

8. 1913-Bohr Planetary model of atom Electrons move in an orbit Each orbit had a definite energy

9. Quantum Mechanical Model

10. e - “cloud” : likely location of e - (90% chance) e - move like waves 1926- Schrodinger

11. Quantum Mechanical Model

12. Dalton 1802 Thompson 1904- “plum pudding” Rutherford 1911 Bohr 1913 “planetary model” Quantum mechanical model History of Atomic Models