Is the mass of an atomic nucleus greater or less than the sum of the masses of the nucleons composing it? Why don't the nucleon masses add up to the total nuclear mass?
there is a small difference due to binding energy. E = m c^2, to get energy, you must lose mass.
The mass of an atomic nucleus is slightly less than the sum of the masses of the nucleons composing it. This phenomenon is known as the mass defect in nuclear physics.
To understand why the nucleon masses don't add up to the total nuclear mass, you need to consider Einstein's famous equation, E=mc², where E is the energy, m is the mass, and c is the speed of light. This equation shows that mass can be converted into energy and vice versa.
In the nucleus, the protons and neutrons are held together by the strong nuclear force. However, this force is not strong enough to overcome the electromagnetic repulsion between the positively charged protons. Therefore, some energy is required to keep the nucleus stable.
Due to this energy requirement, a small amount of mass is converted into binding energy to hold the nucleons together. This mass is called the mass defect. According to Einstein's equation, this mass defect corresponds to a significant amount of energy.
By measuring the total nuclear mass and subtracting the sum of the masses of the individual nucleons, scientists can calculate the mass defect and, subsequently, the binding energy of the nucleus. This energy is released during nuclear reactions, such as fission or fusion, and plays a crucial role in various nuclear applications, including power generation and weapons.
In summary, the mass of an atomic nucleus is less than the sum of the masses of its nucleons due to the conversion of some mass into binding energy to hold the nucleus together.