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B Conservations in nuclear reactions

  1. Mar 25, 2017 #1
    Is the atomic number and mass number conserved in nuclear decays?
     
  2. jcsd
  3. Mar 25, 2017 #2

    vanhees71

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    No! Take ##\beta## decay, where within a nucleus a neutron decays to a proton, electron, and antielectron neutrino. The daughter nucleus has the same number of nucleons ##A'=A## but ##Z'=Z+1##.

    For ##\alpha## decay a nucleus emits a ##_2^4\mathrm{He}## nucleus, i.e., the daughter nucleus has ##A'=A-4## and ##Z'=Z-2##.

    https://en.wikipedia.org/wiki/Radioactive_decay#Types_of_decay
     
  4. Mar 25, 2017 #3

    Vanadium 50

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    What decays have you looked it? Are the atomic number and mass number conserved in those decays?
     
  5. Mar 25, 2017 #4

    Fervent Freyja

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    Usually not, but that depends upon the type of decay...
     
  6. Mar 25, 2017 #5
    So mass number is conserved but not atomic number...
     
  7. Mar 25, 2017 #6

    mfb

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    Right (assuming you count all invovled particles, e.g. including the alpha nucleus in an alpha decay).

    The conservation of the sum of mass numbers is equivalent to baryon number conservation. While it is expected that there are processes changing it, it has never been observed.
     
  8. Mar 25, 2017 #7

    Fervent Freyja

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    In the case of gamma decay, both are conserved (most of the time).
     
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