I have some questions from reading my Intro to Nuclear engineering text book and did not want to take over Dlockwood's thread. Why does the atomic number increase when a beta particle is released? Passage from my text book: "The nuclear fission process, as one method of converting mass into energy, is relatively inefficient, since the "burning" of 1 kg of uranium involves the conversion of only 0.87 g of matter into energy. This corresponds to about 7.8 x 10^13 J/kg of the unranium comsumed."* I read this but the J/kg is throwing me off what the author means. Is it that for every 0.87g of uranium, 7.8 x 10^13 J of energy is released? I can not find it in context, but I think I remember MeV being used to represent mass. Is this a valid way to represent small amounts of mass? *Nuclear Energy: An Introduction to the Concepts, Systems, and Applications of Nucler Process. Fifth edition, 2001. Raymond L. Murray.