# Mass Defect: Is my understanding correct?

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In summary, according to Einstein's special theory of relativity, there is a direct relationship between mass and energy where an increase in one results in an increase in the other. This is represented by the famous equation ##ΔE=Δmc^2##, where 'c' is the velocity of light. Additionally, the mass of an atomic nucleus is less than the sum of its individual nucleons, known as the mass defect. This can be expressed as ##m_x<Zm_p+Nm_n##. The binding energy of a nucleus is the minimum energy required to separate its nucleons and is equal to the nucleus' mass defect. It has been found that iron-56 and nickel-62 have the highest nuclear binding
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TL;DR Summary
I want to write a student article specially for those who don't have a background in nuclear physics. I've been suggested to share my basic understanding & ask if they're correct.
I would be grateful if anyone could explain where my mistakes are:
(Please note that diagrams are designed just to give a simple imagination of the article & make it more understandable; they do NOT correspond precise information.)
Mass – Energy Relationship:
According to Einstein’s special theory of relativity, when the energy of a body increases, so does its mass, and vice versa. If the difference in energy is indicated by ΔE and the difference in mass by Δm, these two quantities are related by his famous equation:
##ΔE=Δmc^2##
When 'c' is the velocity of light (##2.9979×10^8 m/s##).

Mass Defect:
The mass of an atomic nucleus is less than the sum of the individual masses of the free constituent nucleons, this 'missing mass' is known as the mass defect. So for a nucleus (X) with Z protons and N neutrons we can write:
##m_x, m_n ,m_p## -the masses of a nucleus (X), free neutron and free proton
##m_x<Zm_p+Nm_n##
Mass Defect= ##Zm_p+Nm_n-m_x##

As it has been written in the first part, nuclear binding energy is the minimum energy we need to add to a nucleus to separate all of its nucleons.
So for the binding energy of that nucleus (##B_x##) we could write:
##m_x+B_x=Zm_p+Nm_n##
##B_x=Zm_p+Nm_n–m_x##
And we can conclude that the binding energy of a nucleus corresponds/is its mass defect [by ##E=mc^2##].
Iron-56 and nickel-62 have the highest nuclear binding energy per nucleon; meaning that they have the least mass per nucleon. As a matter of fact 'more tightly bound means less massive.'References:
https://www.physicsforums.com/posts/6216782/https://chem.libretexts.org/Bookshe...x)/Miscellaneous/460:_Mass-Energy_Equivalence

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Seems OK except that you're mixing units in your binding energy equations. Because ##E = mc^2## not ##E = m##, there should be a factor of ##c^2## in there, unless you've explicitly stated somewhere that you're using units where ##c = 1##.

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Yes you're right, but to be honest, I've already given up writing that article.

## 1. What is mass defect?

Mass defect is the difference between the mass of an atom's nucleus and the sum of the masses of its individual protons and neutrons. It is caused by the conversion of some mass into energy during nuclear reactions.

## 2. How is mass defect calculated?

Mass defect is calculated by subtracting the actual mass of the nucleus from the sum of the masses of its individual protons and neutrons. This difference is then converted into energy using Einstein's famous equation, E=mc^2.

## 3. What is the significance of mass defect?

The significance of mass defect lies in the fact that it is responsible for the release of energy during nuclear reactions. This energy is what powers the sun and other stars, and is also harnessed in nuclear power plants.

## 4. Does every atom have a mass defect?

Yes, every atom has a mass defect. However, the amount of mass defect varies depending on the size and composition of the atom's nucleus. Generally, larger atoms have a greater mass defect compared to smaller atoms.

## 5. Can mass defect be observed in everyday life?

Mass defect is not directly observable in everyday life. However, its effects can be seen in the release of energy during nuclear reactions, such as in nuclear power plants or nuclear bombs. It also plays a crucial role in the formation and stability of elements in the universe.

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