Recently the radation physics class I am taking reviewed decay and I wondered how beta minus decay and electron capture can both emit neutrinos. I tried asking my professor, but I do not think I explained my question well enough to him. To explain my mindset, imagine you have only one radioactive atom in the middle of a few electrons, nothing else exists that can influence them. The atom undergoes beta decay, emits an antineutrino, and captures a nearby electron to remain neutral. Now the atom undergoes electron capture and emits another neutrino. You are back where the cycle started, but down the energy of the two neutrinos, a small amount - but it is missing. Eventually that energy will add up if the cycle continues, so where does it all come from? What is wrong with my reasoning above?