Democritus

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Democritus

• a Greek philosopher (450 BC)
• Small indivisible units of matter
• Called them Atomos

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Atom

• Smallest particle of an element that retains the
  chemical identity of that element

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Comparison

• World population6,000,000,000
• Atoms in Cu penny29,000,000,000,000,000,000,000

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Molecule

• Smallest particle of a compound that retains the
  chemical identity of the compound

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Daltons Atomic Theory

• All matter is made up of atoms small
  indivisible, indestructible particles
• All atoms of the same element are exactly alike
  (mass, chemical behavior,)
• Atoms cannot be created, nor destroyed, nor
  divided into smaller particles.

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Daltons Atomic Theory -cont.

• Different atoms combine in whole number ratios to
  form compounds.
• Chemical reactions cause atoms to separate,
  combine or rearrange.

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Review 1 Who first came up with the idea that
matter is made up of atoms?
Democritus
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Review 2 Dalton said matter is made up of
atoms small, indivisible, ?
particles
indestructible