The mass of a 2010Ne atom is is 19.99244 amu. How do you calculate its mass defect?

1 Answer
anor277
Jan 12, 2017

By taking the difference between the sum of the nucleon masses and the atomic mass.

Explanation:

I will not consider electronic mass here. We know (the masses should have been provided in the question!) that the neutron mass is 1.008701⋅amu and the proton mass is 1.007316⋅amu.

Given 10 protons and 10 neutrons, there combined mass is 10×{1.008701+1.007316}⋅amu=20.16017 amu.

And thus the mass defect is, 20.16017 amu−19.99244 amu
=0.16773⋅amu. And this seems a rather large value? I would check this with your text, or with someone who deals with particle physics problems. You are in the chemistry section, and certainly I don't have a feel for the right order of magnitude here.

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