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?

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.

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

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.

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

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.

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.

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

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

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

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