Chapter 25 Nuclear Chemistry

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Chapter 25 Nuclear Chemistry

• Ch. 25.1 Nuclear Radiation

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Radioactivity

• Radioactivity is the process by which materials
  give of rays and particles. The rays and
  particles given off are referred to as radiation.
• Nuclear reactions are different from chemical
  reactionsthe nuclei change instead of the
  electrons.
• Radioisotopesunstable isotopes that gain
  stability when the nuclei undergo changes.

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• Nuclear reactions are not affected by changes in
  temperature, pressure, or catalysts, and a given
  radioisotopes nuclear reactions cannot be
  speeded up, slowed down, or stopped.
• Too many or too few neutrons relative to protons
  makes a nucleus unstable. An unstable nucleus
  released energy by emitting radiation during the
  process of radioactive decay.

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Types of Radiation

• Alpha Radiationconsists of helium nuclei that
  have been emitted from a radioactive source
  (alpha particletwo protons and two neutrons).
• Alpha particles have a 2 charge and an mass
  number of 4.
• Alpha particles have low penetrating power, but
  alpha emitting radioisotopes are dangerous when
  ingested.

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Beta Radiation

• A beta particle is created when a neutron in an
  atom breaks apart into a proton and an electron.
  The proton remains in the nucleus, and the
  fast-moving electron is released.
• A beta particle has a -1 charge, and a mass of
  1/1837 amu.
• Higher penetrating power, but can be stopped by
  wood or metal foil.

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Gamma Radiation

• Gamma rays are high energy photons
  (electromagnetic radiation) emitted by
  radioisotopes.
• Often accompany alpha or beta particles during
  radioactive decay.
• No mass or electrical charge.
• High penetrating power. Can be partially stopped
  by dense materials such as lead, steel, or
  concrete. Dangerous.

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