Question #d3263

1 Answer
Oct 7, 2017


Actually, germanium-71 does not undergo beta decay.


The interesting thing to point out here is that germanium-71 does not undergo beta decay, it actually undergoes electron capture #-># see here.

When germanium-71 undergoes electron capture, its nucleus captures an electron from one of its inner energy shells, which results in the conversion of a proton to a neutron.

Consequently, the atomic number of the nuclide will decrease by #1#. On the other hand, its mass number will remain unchanged.

At this point, the nucleus emits an electron neutrino, #nu_e#.

The balanced nuclear equation that describes the electron capture of germanium-71 looks like this

#""_ 32^71"Ge" + ""_(-1)^(color(white)(-)0)"e" -> ""_31^71"Ga" + nu_e#

Notice that you have

  • #71 + 0 = 71 -># conservation of mass

  • #32 + (-1) = 31 -># conservation of charge

The resulting nuclide is galium-71.

Now, in a beta decay, the nucleus of a radioactive nuclide emits a beta particle, which is another name given to an electron, and an electron antineutrino, #bar(nu)_e#, as a result of the fact that a neutron is being converted into a proton.

This time, the atomic number of the nuclide increases by #1# and its mass number remains unchanged.

So assuming that germanium-71 undergoes beta decay, the balanced nuclear equation looks like this

#""_ 32^71"Ge" -> ""_ 33^71"As" + ""_(-1)^(color(white)(-)0)"e" + bar(nu)_e#

Once again, you have

  • #71 = 71 + 0 -> #conservation of mass
  • #32 = 33 + (-1) -># conservation of charge

This time, the resulting nuclide would be arsenic-33.