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## Homework Statement

I am preparing a presentation on nuclear reactor technology.

To demonstrate the mass-energy equivalence, I am trying to calculate the binding energy of some heavier isotopes. The problem is that, when I substitute the values that I have into the equation, I get a binding energy that is substantially below what I have found in a range of sources.

## Homework Equations

[tex]E_{B} = (Zm_{p}+Nm_{n}-^{A}_{Z}m)c^{2}[/tex]

## The Attempt at a Solution

Substitution, using uranium 235 as an example:

[tex]E_{B} = ((143*1.007974)+(92*1.0086649156)-235.04393005)931.5*10^{6}\frac{eV}{c^{2}} [/tex]

[tex]=1763.81777851379 MeV[/tex]

But the binding energy reported in the same source that the atomic mass came from was 1783.890991 MeV, which is substantially more than my result.

I understand that I need to be using the

*neutral atomic mass*, but quite honestly, I don't know what that means exactly, and I don't know where to find it. I tried subtracting the electron masses from the atomic mass, but then I ended up with a binding energy that was too large.

A textbook I have used an abridged table that was lifted from a nuclear physics textbook (which I don't have).

What am I doing wrong here?

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