Give a general explanation of alpha and beta decay.  Provide an example of each.

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mwmovr40 eNotes educator| Certified Educator

In nuclear alpha decay an unstable nucleus changes by emitting an alpha particle.  An alpha particle consists of two protons and two neutrons joined together, or one can also think of it as a helium j+2 ion.  When this happens, the atomic number of the parent atom is reduced by 2 and the mass number is reduced by 4.

For example:

Americium-245 ---> Neptunium-241  +  Alpha

Neptunium has two less protons (2 less Atomic Number) and 4 less mass number than Americium-245


In nuclear beta decay one neutron in the parent nucleus becomes unstable and decays into a proton and an electron.  The proton stays in the nucleus and the electron is ejected.  Because the parent nucleus loses a neutron, but gains a proton its mass number remains the same.  However, because it has gained a proton, its atomic number goes up by one.

For example:

Fluorine-15  ----> Neon-15  + beta

Neon has one more proton than fluorine.