Please tell me if my assumption is correct. So nuclear fusion does not occur with nuclei (with a nucleon number higher than 56) because the binding energy of the product nucleus is lower than the binding energy of the nuclei fusing together. Due to the product nucleus having a lower binding energy (and thus lower mass defect), this must mean that mass has been gained through the reaction which is impossible because energy is released...????
Please let me know if I am wrong, I am really struggling to understand the concept of binding energy :(