1. The problem statement, all variables and given/known data The question is longer than this but the part I'm stuck on is this - Show that the ground state of 8Be is stable against nucleon emission. 2. Relevant equations I'm not sure which ones to use... I used the binding energy formula. 3. The attempt at a solution what i'm not sure about is that in our textbook it says you need to look at the energy difference between neighboring isobars and if the difference in energy is greater than the nucleon binding energy then you get nucleon emission. So now does this mean I look at 8Be, 8B, 8Li and compare the binding energies? If I do this I see a difference of 17MeV or so, which is greater than the nucleon binding energy of 7MeV. If I instead look at 8Be, 7Li and 7Be I have the same problem - there is a big difference. Now this would indicate to me that there is in face nucleon emission. What am I doing wrong?