Each of the following nuclei undergoes either beta decay or positron emission. Predict the type of emission for each: (b) 8938Sr.

Video transcript

Hey everyone where asked will the new cli, barium 1 38 undergo beta decay or positron emission. To answer this question, we first need to determine our N over Z ratio which is essentially our atomic mass minus our atomic number. All over our atomic number. As we've learned, our atomic mass is the sum of the protons and the neutrons. And our atomic number tells us the number of protons. So when we subtract our atomic number from our atomic mass, we end up with our number of neutrons Plugging in these values, we got 1:38 -56. And we're going to divide all of this by 56. So when we calculate this out, we end up with a neutron to proton ratio of 1.46. Now, in order to determine the stability of an isotope. This depends on our energy ratio. Since our atomic number is in between the values of 40 And 80, this means that our N over Z ratio must be equal to 1.50 in order to be considered stable. And as we can see right here, our neutron to proton ratio is less than 1.50, which essentially means we are below the valley of stability. Now, since we're below the valley of stability, this means we have too many protons, so we are most likely to undergo positron emission and this is going to be our final answer. Now, I hope that made sense. And let us know if you have any questions