Question

I am basically confused as why can't larger nuclei undergo fushion and release energy. One reason I know is because of too much protons than neutrons which generates stronger electrostatic repulsive forces.But another reason is something related to binding energy per nucleon which is making it difficult for me to understand.

Answer 1

Larger nuclei struggle to undergo fusion primarily due to the increased Coulomb repulsion with more protons and the flattening of the binding energy per nucleon curve beyond iron, which makes fusion for these heavier elements require energy instead of release it.

Step-by-step explanation:

Larger nuclei face a significant hurdle in undergoing fusion due to the Coulomb repulsion between the positively charged protons within them. This electrostatic repulsive force increases with the number of protons, making it more difficult for larger nuclei to get close enough for the short-ranged attractive nuclear force to cause fusion. Furthermore, the concept of binding energy per nucleon comes into play.

This is the amount of energy required to remove a nucleon from a nucleus. In lighter elements, the binding energy per nucleon increases with mass, which is why fusion up to iron releases energy. However, past the element iron, the curve flattens, and larger nuclei have roughly the same or even lower binding energy per nucleon. As a result, fusing larger nuclei requires additional energy, as opposed to releasing it.