SCI 270: On Nuclear Technology Practice Problems  

7. Stable and Radioactive Nuclides

  1. What are the number-of-neutrons to number-of-protons ratio for the stable nuclides:

    1H_1_ 14N___ 35Cl___ 56Fe___ 80Br___ 100Rh___ 150Sm___ 200Hg___ 209Bi___

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    The purpose is to work out the ratios yourself so that you realize how the numbers of protons and the numbers of neutrons in stable nuclides vary. This is an important factor contributing to the stability of nuclides.

     

     

  2. Magic numbers contribute to the stability of nuclides. From a source other than SCI270 lecture notes, find the stable isotopes for the following:

    Source:
    4He2
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    6Li3 7Li3
    16O8
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    14N7The only one
    40Ca20
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    45Sc21The only one
    54Fe2656Fe, 57Fe, 58Fe 59Co27The only one
    58Ni28
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    63Cu2965Cu29
    112Sn50
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    121Sb51123Sb51
    204Pb82
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    209Bi83Number of neutron = _____
    The only one

    Double magic number nuclides: ___________________________
    For your information, 209Bi (Z = 83) is stabe, whereas 209Pb (Z = 82) is a beta emitter.

     

     

  3. Provide the (missing) masses in amu, calculate binding energies (BE) in MeV, average binding energies in MeV, and the mass excess in MeV of the following nuclides. Masses of hydrogen and neutron are 1.007825 and 1.008665 amu respectively.
    Nuclide2D 4He 14C 14N 16O 56Fe 59Co 238U
    Mass
    _______
    4.00260
    _____
    14.003074 15.994915 55.9349 58.9332 238.0508
    Binding
    energy

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    Average
    BE

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    _____

    _____

    _____

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    _____
    Mass
    excess

    _______

    _____

    _____

    _____

    _____

    _____

    _____

    _____

     

     

  4. The disintegration energies for isobars with mass number 133 are given below. Make a plot of energy content as a function of Z for these isobars from the disintegration energy (in MeV). Te (Z=52), 2.4; I (Z=53), 1.8; Xe (Z=54), 0.43; Cs (Z=55), stable; Ba (Z=56), 0.489; La (Z=57), 1.2l Ce(Z=58), 1.8.

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      Answers to Practice Problems 7 are available, but do your part first. Your skills earn you a rewarding career and they are yours forever.

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