Are your parents/guardians coming to open house tonight?

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Are your parents/guardians coming to open house
tonight?

1. Yes
2. No

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Vocabulary Week 6

• atomic number
• atomic mass
• alpha radiation
• gamma radiation
• isotope

• cavil
• charlatan
• ebullient
• ambient
• eclectic

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Atomic number is the _____ number and it tells
how many ______.

• a. bottom, protons neutrons
• b. bottom, protons
• c. top, protons neutrons
• d. top, protons

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An isotope is an atom with the same number of
_______ but a different number of ________.

1. neutrons, protons
2. protons, neutrons
3. protons, electrons
4. electrons, protons

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Review

• Calculate the atomic mass
• 1H 12
• 2H 48
• 3H 40

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Nuclear reactions involve changes in an atoms
___________ while chemical reactions involve
changes with _________________.

1. nucleus, electrons
2. electrons, nucleus

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Radioactivity

• Chemical reaction involves only an atoms
  electrons the nucleus remains unchanged
• Nuclear reaction involves a change in an atoms
  nucleus (p or n0)
• Radioactivity is when substances spontaneously
  emit radiation
• The rays and particles emitted are radiation

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The reason why atoms undergo radioactive decay is
to become unstable.

1. True
2. False

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Radioactivity

• When there are too many protons vs neutrons, the
  positive charges will repel each other causing
  the atom to be unstable
• Unstable ? radioactive decay ? stable
• ? ? radioactive decay ? ?

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The following show the correct order of strength
of radiation from strongest to weakest.

1. alpha, gamma, beta
2. alpha, beta, gamma
3. gamma, beta, alpha
4. gamma, alpha, beta

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Nuclear Reactions

• Alpha Radiation
• a 2 protons 2 neutrons
• Can be stopped with paper (tissue paper)
• 241 237 4
• 95 93 2

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Nuclear Reactions

• Beta Radiation
• ß
• negative charge
• Fast moving electron
• Can be stopped with foil (think aluminum foil)
• 14 14 0
• 6 7 -1

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Nuclear Reactions

• Gamma Radiation
• Energy released from breaking bonds in nucleus
• Occurs with a or ß radiation
• Can be stopped with lead or concrete
• 238 234 4 0
• 92 90 2 0

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• Conversion of an atom of one element to an atom
  of another element is called transmutation.

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Half Life- pg 817

• Time it takes for ½ of radioisotopes nuclei to
  decay
• Each element has a unique half life
• Polonium-214 163.7 microseconds
• Radon-222 3.8 days
• Carbon-14 5730 years
• Uranium-238 4,460,000,000 years

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Half Life

• Either memorize formula OR
• Amount remaining initial amount x (½ )n
• Where n is the number of half lives that passed
• Amount remaining initial amount x (1/2)t/T
• t elapsed time, T duration of half life (must
  be in same units!)
• Draw Pictures

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• The carbon-14 in a sample of bone has ¼ of its
  original amount. How old is the bone? (Carbon-14
  has a half-life of 5730 years)

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• 2. Only 1/8th of the original dose of radon-222
  remains in a test subject. How long ago was the
  radon introduced into the test subjects body?
  (Radon-222 has a half-life of 3.8 days)

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• 3. Barium-139 has a half-life of 43 minutes. How
  many hours will it take to degrade to 1/32nd of
  its original amount?

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• 4. Polonium-211 has a half-life of 3.2 days.
  How long will it take to degrade to 1/128th of
  its original amount?

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• 5. Cobalt - 60 is used to detect leaks in water
  lines. It has a half life of 38 hours. It can not
  be detected by the sensors after it reaches 1/32
  of its original amount. How many days do
  engineers have to test the water lines before the
  Cobalt 60 is undetectable?

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Gas prices keep going up, up, and up.
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• The problem now is that cars have to be plug in
  everyday

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Nuclear Fission

• Process of one atom breaking down into smaller
  atoms
• http//lectureonline.cl.msu.edu/mmp/applist/chain
  /chain.htm

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• Biggest problem with nuclear power is the nuclear
  waste
• Currently, the depleted uranium is stored
  underground in Yuma, Arizona.

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Nuclear Fusion

• Fusion is the process of combining 2 smaller
  atoms into one larger atom
• Produces 10 times more energy than fission
• No nuclear waste! ?

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Recap

• Radiation Penetration
• Alpha a
• Beta ß
• Gamma ?
• Nuclear power
• Biggest problem?
• Waste disposal or nuclear meltdown?

• Fission
• Fusion