What are Atoms?

1
Atoms and the Periodic Table

• What are Atoms?
• History of the Atom
• Whats in an Atom?
• What is the Periodic Table?
• How are Elements Classified?

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What are Atoms ?

• Smallest particle of matter that cannot be
  subdivided
• Make up everything
• Building blocks of molecules
• Atoms of the same element are the same
• Atoms of different elements are different

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History of the Atom

• Democritus
• 4th century B.C. Invented the word Atomos
• John Dalton
• 1808 - English school teacher
• J.J. Thomson
• 1897 - Discovered the electron, Plum Pudding
  Model
• Ernest Rutherford
• 1911 - gold foil experiment, protons at center
  with electrons surrounding compact center

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History of the Atom cont.

• Neils Bohr
• 1913 - Planetary Model
• Modern Atomic Theory
• 1925 Electrons behave like waves on vibrating
  string. Electron Clouds proposed.

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Whats in an Atom

• Electron
• - Charge
• Found in Cloud Surrounding Nucleus

• Proton
• Charge
• Found in Nucleus

• Neutron
• Neutral Charge
• Found in Nucleus

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What is the Periodic Table?

• The Periodic Table is an tool to classify all
  known elements and their properties into Groups
  and Periods

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How are Elements Classified?

• Groups Atoms of elements in the same group, or
  column, have the same number or valence, so these
  elements have the same properties. There are 8
  groups.
• Periods The horizontal rows. Each successive
  row stands for an additional electron shell.

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Resources

• http//www.sciencethings.com/the_store/periodic_ta
  ble/htdocs/magnet.html
• http//office.microsoft.com/clipart/results.aspx?l
  cen-usScopeMC2CMM2CMP2CMSQueryatom