Atomic Theories

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Atomic Theories
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Describe this muffin- Period 1
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Describe this Baseball- Period 1
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Describe this peach- Period 1
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Describe this onion- Period 1
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Describe this muffin- Period 3
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Describe this Baseball- Period 3
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Describe this peach- Period 3
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Describe this onion- Period 3
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Describe this muffin- Period 5
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Describe this Baseball- Period 5
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Describe this peach- Period 5
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Describe this onion- Period 5
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Describe this muffin- Period 6
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Describe this Baseball- Period 6
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Describe this peach- Period 6
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Describe this onion- Period 6
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Review from reading

• An atom is made up of protons, neutrons and
  electrons.
• The protons and neutrons are found in the nucleus
• There has to be an equal number of protons and
  electrons
• Atomic mass is the number of protons and neutrons
• Atomic number is the number of protons (which is
  the same as the number of electrons)

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John Dalton

• Early 1800s
• Pool Ball/Bowling Ball
• Thought atoms were smooth, hard balls.
• Cannot be broken into smaller pieces or divided
• All elements are made of atoms
• Atoms of different elements have different masses
  and characteristics
• An atom of one element cannot be changed into an
  atom of a different element.
• Atoms cannot be created nor destroyed only
  rearranged.
• Compounds are made of atoms from different
  elements

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J.J. Thomson

• 1897
• Berry or chocolate chip muffin
• An atom consists of negative charges scattered
  throughout a ball of positive charges.

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Ernest Rutherford
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• (one of Thomsons students)
• 1911
• Peach
• Positive charge (protons) is located in the
  center of the atom
• Center is called the nucleus.
• Almost all of the atoms mass is located in the
  nucleus.
• Atom is mostly empty space with the electrons
  moving around the nucleus.

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Neils Bohr

• (student of Thomsom and Rutherford)
• 1913
• Sliced Red onion Planets in the solar system
• Electrons could have only specific amounts of
  energy, leading them to move in certain orbits

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Modern Scientists

• 1920s
• Fan/Cloud
• Electrons do not orbit the nucleus like planets
• Electrons are in a cloudlike region around the
  nucleus.
• Electrons of the same energy are in the same
  energy level.

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James Chadwick

• 1932
• Fan/Cloud
• Found that the atom has a particle that was
  electrically neutral (neutron).

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Review Questions

• 1. How is Thompsons atomic model different than
  Daltons?
• 2. How is Bohrs atomic model different than
  Rutherfords?
• 3. What did James Chadwick add to the modern
  atomic model?