Download Discovery of the Atom

Lesson 2.1 – Atomic Structure
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History of the Atom
Discovery of the Atom
Timeline
Ancient Philosophers
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Democritus (460-370 bc)
All matter is composed of individual atoms
that are indivisible and solid
Atoms move through empty space
No experimentation was done
Ancient Philosophers
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Aristotle (384-322 BC)
Disagreed with Democritus
Didn’t believe in empty space
Democritus' idea for the atom was ignored for
over 2000 years
John Dalton (1768-1828)
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Dalton’s Theory (1808)
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Matter is composed of extremely small indivisible
particles called atoms
Dalton’s Theory Continued
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All atoms of a given element are identical,
(size, mass, properties). Atoms of a specific
element are different from those of any other
element.
Dalton’s Theory Continued
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Atoms can’t be created, destroyed or divided
Dalton’s Theory Continued
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Atoms combine to form compounds
Dalton’s Theory Continued
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In a chemical reaction, atoms are separated,
combined, or rearranged.
Dalton’s Theory Continued
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*** These are almost all right – which one’s
aren’t?