PS 101

1
PS 101

• Kim Cohn
• Email address
• Kcohn_at_academic.csubak.edu

2
How to Obtain Slides

• A CD-R disc can be checked out from the library
  2 hour reserve.
• The disc can be duplicated at the library.
• You can take it home and duplicate it.
• I have a few for sale.
• 5.00 need bills, not checks.

3
Elements

• Everything that you touch is called matter or
  chemicals
• All matter is composed of atoms
• There are about 112 different types of atoms
• Each type of atom is called an element
• Separate atoms are too small to be seen

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Comments- Todays Demo

• The light stick in the cold water does not glow
  as brightly as the light stick in the warm water.
  Why not?
• What would happen if I put the hot light stick in
  the cold water and visa-versa?

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Elements 2

• Atoms themselves are made up of three smaller
  particles, the electron, the neutron and the
  proton.
• The electron is the smallest of the three, has a
  charge of 1 and a relative weight of 1.
• The proton and neutron have a relative weight of
  about 2000 and a charge of 1 and 0 respectively.

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Elements 3

• The proton and neuton are found at the center of
  an atom or nucleus.
• The nucleus is small compared to the size of the
  atom.
• The electrons are found outside the nucleus and
  take up room, not because of their size but
  because they are moving around.

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The Electron

• A voltage (electric potential energy per charge)
  placed across a sealed glass tube produces a ray,
  called a cathode ray because it comes from the
  cathode or negative electrode.
• The ray was found to consist of a stream of small
  particles with a small mass and a charge of 1.
• These particles are called electrons.

8
The Nucleus

• Rutherford shot small positively charged
  particles at gold foil thinking most would be
  stopped.
• Most of the positively charged particles went
  through the foil unchanged.
• This experiment showed that most of the atom is
  empty.
• It also showed most of the positive particles in
  the atom (the protons) take up little space in
  the center of the atom.

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Protons and Neutrons

• The number of protons determine the nature of the
  atom. An atom with one proton is hydrogen, two
  protons helium.
• The number of protons is called the atomic
  number.
• The neutron is also found at the center of the
  atom.
• The number of protons and neutron is called the
  atomic mass.
• Two atoms with the same number of protons but
  different numbers of neutrons are called isotopes.

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Bohrs Model

• The nucleus of an atom (the total number of
  protons and neutrons at the center of an atom) is
  surrounded by electrons.
• The electrons circle the atom much as planets
  circle the sun.
• If an electron moves from an inner to an outer
  orbit it will absorb energy in the form of light.
• If an electron moves from an outer to an inner
  orbit it will release energy in the form of
  light.
• The light may be visible, infrared, ultraviolet,
  or even x-ray.

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Bohrs Model in One Dimension
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Quantum Mechanics

• Electrons exist in two forms, particles and waves
  at the same time.
• The electron wave surrounds the nucleus much as
  water would surround a flooded planet.
• The electron wave will exist only if it is a
  standing or reinforced wave.
• The electron can moves from an outer to an inner
  wave or from one type of wave to another.
• When it moves it will release or absorb energy,
  just like the Bohr model.

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Quantum Mechanics in One Dimension
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Quantum Mechanics in One Dimension - 2
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Quantum Mechanics in One Dimension - 3
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Arianism

• Arius preached that the Son was not equal with
  the Father but was subordinate to Him.
• Declared a heresy at the Council of Nicea (325
  CE).
• The council was called by the Constantine.
• Constantine made Christianity the religion of the
  State.

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Questions

• What makes one element different from another?
• The atomic number of an atom that contains 32
  protons, 30 neutrons and 31 electrons is?
• Most of the weight of matter comes from?
• The model that explains why electrons orbit at
  specific distances from the nucleus involves?
• Where did the matter that you are made up of
  originally come from?