Famous Science Atom Guys

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Famous Science Atom Guys
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Democritus

• Philosopher
• All matter consists of small particles that
  CANNOT be divided
• He called these particles ATOMS (Greek for
  indivisible)

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Dalton

• Teacher interested in weatherand the behavior of
  gasses in the air
• Worked with MASSES of elements and compounds
• All matter is made up of atomswhich cannot be
  divided

FALSE
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Main points of Daltons Theory

• All elements are composed of atoms
• All atoms of the same element have the same mass
• Atoms of diff. elements have diff. masses.
• Compounds contain atoms of more than one element
• Atoms of diff. elements always combine in the
  same way.

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Daltons Atom
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Thomson

• Electric current flow of charge from one
  particle to another
• Thomson used a sealed tube of gas to conduct an
  experiment to understand this current and the
  charges of atoms

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• Thomsons experiments provided the first evidence
  that atoms are made of even smaller pieces
• Atom neutral
• Atom contains positive and negative particles

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Thomsons Model
Balance (,-) neutral Evenly scattered!

• Vanilla ice cream positive mass
• Chips negative particles

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Rutherford

• Alpha particles fast-moving positive charged
  particle
• If direct this alpha particle through an atom -
  if the (-) charges are evenly spaced.then the
  path of the alpha particle shouldnt change
• But.it did

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• The path was deflected when it hit the NUCLEUS
• The nucleus was discovered!!!

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What happened?

• Alpha particle ()
• Came in contact with another () to repel or
  deflect the path
• Not all the alphas were deflected - so the
  particles ARE NOT equally scattered
• More concentrated deflection in the center of
  atom nucleus ()

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Rutherfords Model

• All of an atoms positive charge is concentrated
  in its nucleus

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• What theory did Dalton propose about the
  structure of matter?
• All matter is composed of individual particles
  called atoms, which cannot be divided

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• What evidence did J.J. Thomson provide about the
  structure of an atom?
• Thomson provided the first evidence that atoms
  are made from even smaller particles

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• What did Rutherford discover about the structure
  of an atom?
• All of the positive charge of an atom is
  concentrated in its nucleus

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• If you observed a beam of particles being bent
  toward a negatively charged plate, what might you
  conclude?
• The particles have a positive charge