Mass defect and binding energy?

Question

How can mass defect and binding endery be calculated?

Answer 1

Figure out the theoretical mass based on the number of protons, neutrons and electrons. You can find the mass of an electron, proton and neutron via yahoo or google or it should be in your textbook. Subtract the actual mass from the theoretical mass to figure out the mass defect(theoretical-actual=mass defect). Then use e=mc² to convert mass to energy to figure out the binding energy.