ATOMS

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					                   ATOMS
atom: the smallest basic unit of matter
• there are more than 100 types of atoms
• matter does not contain atoms…it is atoms!
• although you cannot see them, atoms do have mass.
  500,000,000,000,000,000,000,000 atoms fit into a
                     teaspoon!
                     MOLECULE
• molecule: a particle that is formed when 2 or
  more atoms bond together
• it can be made of atoms that are different or
  alike
• example: 2 hydrogen atoms bond with an oxygen
  atom
                                              O
  H
 This molecule is water!

  H
         Molecules: Some Facts
• What would happen if you divided water to find its
  smallest part?
• Eventually you would have only one molecule of
  water…then what happens if you divide that?
• You no longer have water! You have “H” and “O”, 2
  different substances!
• Molecules made of different numbers of same atom
  are completely different substances: 2 oxygen atoms
  bonded together is an oxygen gas molecule but 3
  oxygen atoms bonded together is an ozone molecule.
• Atoms and molecules are always in motion!
        Matter can be pure or mixed
• most substances around you are mixed,
  for example:
water
                                          fireworks




                                          lemonade




               wood
                   ELEMENTS
• element: a substance that contains only a single
  type of atom
• elements are found on Periodic Table
• there are 118 elements on most Periodic Tables




   gold atoms        gold coin
               COMPOUNDS
• COMPOUND : a substance that consists of 2 or
  more different types of atoms bonded together
• a compound can be very different than the
  elements that make it




    sodium                chlorine



 + water
                     MIXTURES
• mixture: a combination of different substances that
  remain the same individual substances and can be
  separated by physical means
• examples: fruit salad, kool-aid
Comparing Mixtures and Compounds

• The substances in mixtures remain the same
  substances. Compounds are new substances
  formed by atoms that bond together.
• Mixtures can be separated by physical means.
  Compounds can only be separated by
  breaking the bonds between atoms.
           Types of mixtures
• heterogenous: the properties are different in
  different areas of the mixture
• homogenous: when substances are evenly
  spread throughout a mixture, you cannot tell
  one part of the mixture from another

				
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posted:8/27/2012
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