Section 2 review
Radioactive decay is the spontaneous emission of an energetic particle or photon from a nucleus. The three types of radioactive decay are called alpha, beta, and gamma. Radioactive materials are also identified by their half-life, the time in which half of the original atoms have decayed. Carbon dating is an effective method for dating the age of biological relics and is based on the 5,730 year half-life of carbon-14. (See page 1592 for further references to research the historical development of the concept of the weak nuclear force.) Read the text aloud
radioactive decay, alpha decay, beta decay, gamma decay, weak nuclear force, half-life, carbon dating

N= N 0 ( 1 2 ) t/ t ½

Review problems and questions

  1. Research and describe the historical development of the concept of the weak force. Read the text aloud Show
  1. Uranium-235 undergoes beta decay according to this nuclear reaction equation:
    U 92 235 ? Z A + e 1 0
    What is the element and isotope produced? Read the text aloud Show
  1. The unstable uranium isotope 235 undergoes radioactive decay to produce thorium-231 following the equation U 92 235 T 90 231 h+ ? Z A What is the atomic and mass number of the emitted particle? What is the name for this particle and type of decay? Read the text aloud Show
  1. In the radioactive decay equations in questions #2 and 3 above, do you expect the binding energy of the resultant nucleus (or nuclei) to be larger or smaller than the binding energy of the original nucleus? Show
What are these two decay processes?
  1. A two level decay process starting with americium-240 ends up with plutonium-236, as indicated by the arrows on this relevant portion of the chart of nuclides. These two levels are indicated by the arrows marked A and B on the chart of nuclides.

    What are these two decay processes? Read the text aloud Show

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