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Chapter 5
Exam is not graded yet-
I hope to hand them back on Wed
One of the main quests of science
throughout the ages has been to discover
what matter is made of - and what holds it
together.
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Democritus
Greek Philosopher
About 450 B.C
All matter is composed of tiny indivisible particles.
Named these particles
atomos
meaning “indivisible”
Aristotle
Greek Philosopher
About same time as Democritus
Disagreed with Democritus
Did not believe in atoms
4 elements:
Earth
Air
Water
Fire
John Dalton
1803
Dalton’s Atomic Theory of Matter:
Each element is composed of extremely small
particles called
atoms
All atoms of a given element are identical, but they
differ from those of any other element.
Atoms are neither created nor destroyed.
A given compound always has the same relative
numbers and kinds of atoms.
Dalton’s Model of the Atom
:
Billiard Ball Model: the same
throughout
An
An
atom
atom
is the
is the
smallest and simplest
smallest and simplest
unit into
which an element can be divided while
which an element can be divided while
maintaining the properties of the element.
maintaining the properties of the element.