Why is the heaviest element in the Sun iron?
It is interesting to try and answer this question because it is somewhat subtle and, perhaps, one of those magic numbers in nature. The binding energy of a nucleus is a balancing act between the strong force binding the nucleons together and the electrostatic force repelling them apart. It just happens to be at about 58 nucleons the replusive force ‘tips’ the balance so that you have to add energy to add another nucleon. It just so happens that Iron has that balance in stellar fusion. I provided some Hyperphysics links below – these should help.
