Chapter 28 Nuclear Chemistry

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Chapter 28 Nuclear Chemistry

• Nuclear Radiation
• Nuclear Transformations
• Fission and Fusion
• Radiation in Your Life

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Ch 28.1 Nuclear Radiation

• Radioactivity
• Types of Radiation

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Radioactivity

• Radioisotopes an isotope that has an unstable
  atomic nucleus and undergoes radioactive decay
• Always accompanied by large emissions of energy
• Not affected by temp., pressure, or catalysts
• Can not speed up or slow down the reaction or
  turn off

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Radioactivity

• Marie Curie (1867-1934) named the process
• Process by which unstable atomic nuclei achieve
  stability
• Won Nobel Peace Prize 1903 along with Pierre
  Curie and Antoine Henri Becquerel

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Radiation

• Penetrating rays and particles emitted by a
  radioactive source

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Types of Radiation

• Alpha
• Beta
• Gamma

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Alpha

• Helium nuclei emitted from a radioactive source
• Alpha particles
• Contain 2 protons and 2 neutrons and have a
  double positive charge
• 42He or ?
• Can be stopped by a sheet of paper or your skin

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Beta

• Fast moving electrons formed by the decomposition
  of a neutron
• Beta Particles
• 0-1e or ?
• Can be stopped by aluminum foil or pieces of wood

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Gamma

• High energy electromagnetic radiation
• ?
• No mass, no charge
• Can almost be stopped by several feet of concrete
  or several inches of lead

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Chernobyl

• April 26, 1986 at 12344am
• Reactor 4 exploded
• Released 30-40 times the amount of radiation as
  bombing Japan did

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Chapter 28.2 Nuclear Transformations

• Nuclear Stability and Decay
• Half Life
• Transmutation Reactions

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Nuclear Stability and Decay

• 1500 different nuclei, only 264 are stable
• For low atomic number (up to 20), the ratio of
  protons to neutrons is 1(ratio of stability)
• 126C 147N
• Atomic numbers above 20, have a ratio of protons
  to neutrons of 1.5(ratio of stability)
• 20682Pb

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Beta Emissions

• 6629Cu ? 6630Zn 0-1e
• 146C ? 147N 0-1e

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Positron

• Particle with the mass of an electron, but a
  positive charge
• 01e
• 85B ? 84Be 01e

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Alpha Emission

• All nuclei with an atomic number greater than 83
  are radioactive
• 20482Pb ? 20080Hg 42He
• 22688Ra ? 22286Rn 42He

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Half Life

• The time required for one half of the nuclei of a
  radioisotope sample to decay to products

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Artificial Radioisotopes

• Usually have very short half lives
• Used in nuclear medicine

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PET Scan - Positron Emission Tomography
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Brain Function
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Thyroid TumorsDog

• Iodine 131

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Bone Fractures

• Technetium

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• Radioactive Isotope Use
• C-14 Used to determine the age of biological
  remains (archaeology)
• I-131 Used to detect and cure hyperthyroidism
  (overactive thyroid)
• Co-60 Used as a source of radiation for
  radiotherapy of cancer
• Tc-99m Used to image blood vessels, especially in
  the brain, to detect tumors
• Pu-239 Used as a highly fissionable fuel source
  for nuclear power or nuclear weapons
• Am-241 Used in tiny amounts in smoke detectors as
  a source of ions to make a current
• U-235 Used as fissionable fuel source for nuclear
  power or nuclear weapons
• U-238 Used to determine the age of
  uranium-containing rock formations (geology)

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