How does alpha decay affect the nucleus?

1 Answer
Jun 16, 2016

Answer:

In alpha decay the nucleus loses 2 protons and 2 neutrons.

Explanation:

An alpha (#alpha#) particle is similar to the nucleus of a helium atom i.e. 2 protons and 2 neutrons. The atomic mass of the nucleus that emits an #alpha#-particle will decrease by four and the atomic number decreases by two. In general terms:

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In which #X# is a nuclide that exhibits alpha decay and #Y# the resulting nuclide. Due to #alpha#-decay:

  • #A#, the atomic mass (protons + neutrons), decreases by four, because the emitted #alpha#-particle contains 2 protons and 2 neutrons.
  • #Z#, the atomic number (number of protons), decreases by two, because the emitted #alpha#-particle contains 2 protons.

An example of this process is the decay of radium-226 to radon-222:

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Note that sometime #""_2^4 alpha# is given as #""_2^4He# which is essentially the same.