1. A Brief History of the Atom & Atomic Models

2. Democritus 480 B.C. a Greek philosopher
Theorized everything was made out of tiny particles – atoms
Believed that atoms were hard, solid spheres that could not be destroyed
Idea was controversial - had no evidence - no one believed him.

3. Democritus
“The good things of life are produced by learning with hard work; the bad are reaped of their own accord, without hard work."
"Fame and wealth without intelligence are dangerous possessions."

4. John Dalton English school teacher Formed his own atomic theory.
Elements made of tiny particles -atoms.
Atoms cannot be created or divided into smaller particles.
Atoms of a an element are different from those of any other element.
John Dalton

5. John Dalton Had evidence to support his idea - Democritus did not.
Viewed the atom as a hard, solid spheres - could not be broken down.
This theory was disproved by the discovery of electrons
John Dalton

6. J.J. Thompson Discovered electron by using the cathode ray tube.
Cathode rays were stream of (-) charged particles.

7. J.J. Thompson
Model had (+) and (-) charges scattered throughout the atom.
Known as chocolate chip cookie model.
This model was disproven by discovery of the nucleus.
Plum Pudding model

8. Ernest Rutherford Discovered nucleus by the Gold Foil Experiment.
Angles of deflection that alpha particles (+) made proved evidence of a nucleus.

9. Model defines location and charge of nucleus – doesn’t clearly define location of the electrons.
This model is IMPROVED by the Bohr model.
Ernest Rutherford

10. Model depicts atom as small, (+) charged nucleus surrounded by electrons in orbit.
Similar to the solar system, but with forces providing attraction, rather than gravity.
Niels Bohr

12. Create a Flipbook
Create a flipbook for Dalton, Thompson, Rutherford, and Bohr
Include:
Picture of their models
Name of the specific part of the atom they discovered
Explanation of how their model changed to previous ideas of what an atom looked like

13. The Current Atomic Model
The current model is difficult to draw because electrons move freely around the nucleus in 3 dimensions
Similar to people moving around the planet Earth.

14. How could I find you?