Question

Define the terms binding energy, stellar nuclesynthesis and mass defect. Why do lighter elements favor fusion reactions and heavier elements favor fission reactions?

Answer 1

Binding energy: The amount of energy required to separate a particle from a system of particles or to disperse all the particles of the system is called binding energy.

The binding energy of a single proton or neutron in a nucleus is approximately a million times greater than the binding energy of a single electron in an atom.

Stellar nucleosynthesis:

The process by which the natural abundances of the chemical elements within stars change due to nuclear fusion reactions in the cores and overlying mantles of stars is called stellar nucleosynthesis.

Mass defect :

It is defined as the difference between the mass of a nucleus, and the sum of the masses of the nucleons of which it is composed.

The lighter elements favor fusion reactions and heavier elements favor fission reactions.

Nuclear fusion is a nuclear reaction in which two or more atomic nuclei come very close and then collide at a very high speed and join to form a new nucleus. During this process, matter is not conserved because some of the matter of the fusing nuclei is converted to photons.

The fusion of two nuclei with lower masses than iron-56 generally releases energy, while the fusion of nuclei heavier than iron absorbs energy. The opposite is true for the reverse process, nuclear fission.

Nuclear fission is a radioactive decay process in which the nucleus of an atom splits into smaller parts.

This means that generally only lighter elements are fusable, such as hydrogen and helium, and likewise, that generally only heavier elements are fissionable, such as uranium and plutonium.