1. The problem statement, all variables and given/known data Calculate the binding energy per nucleon (J/nucleon) for 4 He - 4.0026u 239-Pu - 239.0522u 2H 2.0141u 56-Fe 55.9349u Which nuclide is the most stable? 2. Relevant equations E=mc^2 3. The attempt at a solution If I know how to solve the first, I can solve the rest. So, calculating for He mass of the measured nucleus is 4.0026u calculated mass= 2(p+n)=2(1.00728u+1.00866u)=4.03188u delta M=-0.2928u E=mc^2 =(-0.2928u)(3x10^8m/s)^2(1.66x10^-27kg/u) =-4.374..x10^-11 The correct answer is -1.13x10^-12 J/nucelon I'm not sure where I went wrong. Thanks for helping!