Suppose we have a beam balance capable of measuring even smallest differences in weights. Now on one side we have a Triton and Deuteron. And on the other side we have He-nucleus and a neutron I want to know which will weigh heavier and why? I saw on a book cover with balance tilting towards the former one thus i concluded that the deuterons and tritons will weigh more but my explanation on that conclusion don't seem to be logical. Is that book cover right or I have been just fooled and my fumndamentals are just checked?