Evolution of atom
- 1. The Evolution of The Atomic Theory
- 2. Democritus Lived: 460BC-370BC Main concepts: Everything is made of atoms Atoms are indivisible (cannot be divided) Atoms are small and solid particles Named the atom (called it “atomos”)
- 3. Dalton Lived 1766-1844 Main concepts: Each element has a different atom and a different atomic weight All atoms of the same element are perfectly identical Atoms cannot be created or destroyed in chemical reactions.
- 4. Thomson Lived: 1856-1940 Main concepts: Discovered that atoms ARE divisible Discovered the electron through his Cathode-Ray experiment Atoms have a much larger mass than electrons Inferred that atoms have a positive charge Plum Pudding Model
- 5. Rutherford Lived 1871-1937 Discovered that there is a small, dense positively charged nucleus Discovered that most of an atoms mass is in it’s nucleus Predicted the existence of neutrons Stated that electrons move rapidly in the empty space around the nucleus Conducted the gold foil experiment Stated that atoms are mostly empty space.
- 6. Bohr Lived 1885-1962 Stated that electrons can only travel at specific distances from the nucleus Stated that electrons can jump between levels/paths around the nucleus Stated that the chemical properties of an element are determined by how many electrons are in the outer shell.
- 7. Chadwick Lived 1891-1974 Discovered the previously unknown part of the nucleus of an atom- the Neutron! Named the neutron because of it’s lack of an electrical charge. His discovery made it possible to create new elements in the laboratory (heavier than Uranium) which was not possible before.
- 8. Electron Cloud Model This is our most modern and accepted model of the atom It differs from Bohr’s model because it states that the electrons can be found in a general region around the nucleus, not specific paths.
- 9. Time for: The atom song! http://www.youtube.com/wat ch?v=vUzTQWn-wfE
- 10. Time for: The atom song! http://www.youtube.com/wat ch?v=vUzTQWn-wfE
Editor's Notes
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