1. History of the Atom:
Early ideas of matter:
Greek Philosophers:
Aristotle ( B.C.)
four elements: Fire, Air, Earth, Water

2. Democritus ( B.C.)
Matter is make of small, solid objects that cannot be divided, created or destroyed
Atoms are constantly moving
Different types of matter are made of different types of atoms
Properties of the atoms determine the properties of the matter

3. Dalton’s Model
Matter is made of atoms that cannot be divided, created or destroyed
During a reaction atoms of one element cannot be converted into atoms of another element
Atoms of one element are identical to each other but different from atoms of another element
Atoms combine in a specific ratio

4. Thomson
Cathode ray tubes: greenish-colored rays travelled from one electrode to the other end
Added charged plate in the middle and the ray bent away from negative charge.
Concluded: Cathode rays are negatively charged - Electrons

5. Thomson’s model

6. Atoms are mostly empty space (Rutherford, 1871-1937)
He shot alpha particles through gold foil and 99% of the particles when right through.

7. Thomson VS. Rutherford

9. Bohr model
Bohr propsed that electrons are circling the positive nucleus and the farther the

10. Lewis Dot Structures