1. Matter: anything that has a mass BUT…. What is matter made up of?
Atomic Structure
Matter: anything that has a mass
BUT…. What is matter made up of?

2. Matter is made up of atoms. An atom is the smallest particle of matter
Matter is made up of atoms. An atom is the smallest particle of matter. It cannot be divided chemically.

3. Hypothesis – First Models Of Matter
There were many scientist that contribute to the development of the first models of matter
They Included:
Aristotle
Democritus
John Dalton
4. J.J. Thomson
5. Rutherford
6. Bohr

4. Continuous Theory Aristotle: Philosopher 300 BC (Greek)
HE PROPOSED THAT:
All matter was continuous –no matter how small a substance was, the original properties were the same.
Matter was made of the four basic elements fire, water, air, earth.
Did not know about atoms.

5. Discontinuous Theory Democritus: Philosopher 300 BC (Greek) particles
HE PROPOSED THAT:
Matter was discontinuous
Matter can be broken into smaller
particles
Defined the term atom

6. First Models
Despite Democritus’ accuracy, Aristotle’s ideas were more widely accepted.
Neither man was a scientist and neither did any experiments.
They were both thinkers and came up with ideas to explain what they saw in the world around them.

7. Atomic Theory Developed by John Dalton
He is known as the father of the Atomic Theory.
He formulated four main points concerning atoms:
Memorize
All matter is composed of tiny indivisible particle called atoms.
All atoms of the same element are identical (same).
Atoms of different elements are different.
During a chemical reaction atoms combine to form new products.

8. Father of the Atomic Theory
Dalton’s Atomic Model
Even today, basic principles of his theory are still true.
His model was modified to explain new observations of later chemists
Father of the Atomic Theory

9. WHO SAID THE FOLLOWING? Democritis Aristotle John Dalton Aristotle
“Matter can be broken into smaller particles”
“All matter is made of earth, fire, air or water”
Democritis
Aristotle
“No matter how small a substance was, the original properties are the same”
“Atoms of different elements are different
John Dalton
Aristotle

10. Key Points to Remember Original Theories
Discontinuous (Democritis) – spaces between particles
Continuous (Aristotle) – no spaces between particles. Four elements – fire, water, earth & air.
Dalton’s Theory – memorize 4 main points

11. Activities
WORKSHEET # 4