If in nuclear fission, the sum of the masses of the resulting atoms is the same as the parent ($\text{U}_{236}$, after fission is $\text{Cs}_{93}$ + $\text{Rb}_{140}$ + 2 neutrons), where does the concept that mass is lost in favor of energy come from? Keeping in mind the formula: $$E=mc^2$$ Are some electrons and protons of the progenitor disappearing in favor of energy?
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The total number of nucleons (protons and neutrons) is the same after nuclear fission as it was before. The energy released in fission comes from the difference in binding energy between the fissile material and its fission products.
gandalf61
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The atomic number is not the same as the atomic mass. The number is just the sum of the counts of protons and neutrons in a nucleus. That number is conserved during fission (be sure to include the escaping neutrons). The mass is an actual measurement and accounts for the masses of the protons and neutrons and the energy content of the nucleus. Therefore your assertion that the masses before and after fission are the same is wrong.
niels nielsen
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