Nuclear Chemistry

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Nuclear Chemistry

Nuclear reactions change the nucleus of atoms
chemical reactions only involve the valence
electrons of an atoms.
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Radioactivity- the process in which some
substances spontaneously emit radiation
(particles and rays of energy).
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Radiation

• High amount of Radiation
• X-rays
• Cosmic

• Low amount of Radiation
• Radio
• Microwaves

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Nuclear History

• Roentgen- x-rays (1895)
• Becquerel- discovered that phosphorescent
  uranium salts give off radiation
• Marie Pierre Curie- worked with Becquerels
  results to identify 2 new elements, polonium and
  radium.
• Rutherford- identified 3 types of radiation

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Types of radiation

• Alpha
• Beta
• Gamma
• Positron
• Electron capture

We will focus on the first three types.
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Alpha radiation
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Beta radiation
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Gamma radiation
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Balancing Nuclear Equations
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alpha decay

• 23892U ? 23490Th _______

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• 23892U ? 23490Th 42He
• 238 ? 234 4 mass
• 92 ? 90 2 atomic

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Alpha decay a

• You try!!!
• 22688 Ra ? _____ _____

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Alpha decay a

• 22688 Ra ? 4 2 He 222 86 Rn
• 226 ? 4 222 mass
• 88 ? 2 86 atomic

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Beta decay

• 23490Th ? ______ ______

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Beta decay

• 23490Th ? 23491Pa 0-1e
• 234 ? 234 0 mass
• 90 ? 91 -1 atomic

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You try!!!

• 6027Co ? 0-1 e ______
• 230 90 Th ? 4 2 He _______
• 146C ? 147 N _____

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• 6027Co ? 0-1 e 60 28 Ni

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• 6027Co ? 0-1 e 60 28 Ni
• 230 90 Th ? 4 2 He 226 88 Ra

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• 6027Co ? 0-1 e 60 28 Ni
• 230 90 Th ? 4 2 He 226 88 Ra
• 146C ? 147 N 0 -1 e

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• Write the nuclear reaction for the decay of
  Am-241. An alpha particle is released.

• 24195 Am ? 42 He 23793Np

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• Many radioactive elements undergo a series of
  decay reactions, releasing different particles
  and raysa decay series.
• Ex. Uranium-238 has 14 decays to reach a stable
  nucleus of lead-206.
• worksheet

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Half Life

• Measures the rate of decay of radioisotopes
• Information of half-life helps scientists to plan
  how long hazardous wastes must be stored
• 1 half-life time it takes for ½ of the atoms in
  a sample to decay

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The half life of element X is 12 years. If you
begin with a sample of 148.0 g, how much is left
in 60 years?
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Nuclear Uses

• Medicine- X rays, cancer treatment, radiotracers
  (ex. Iodine-131 is used to pinpoint thyroid gland
  disorders)
• Energy- using nuclear fission, nuclear reactors
  produce a large amount of energy using a small
  amount of initial nuclear mass (ex. Uranium)

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Nuclear Uses

• Radioisotopes in everyday products- smoke
  detectors use Americum-241.
• Am- 241 decays and gives off alpha
  particles. These alpha particles ionize the air
  by producing a current. When smoke interrupts
  this process, an alarm is triggered in the smoke
  detector.

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Fissionsplitting of nuclei
Fission is used in nuclear reactors to produce
energy.
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Fusioncombining of two nuclei
Fusion occurs in the sun, where 4 hydrogen atoms
and 2 beta particles fuse to form a helium atom.