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Re: Mass excess (was Re: chart of nuclides)



Bob Muir asked:

What IS excess mass?

From Choppin and Rydberg's _Nuclear Chemistry_ (1980, p.39):

Mass excess = M - A

where M = total atomic mass
A = mass number

Mass defect = M - Z*M(H) - N*M(n)

where Z = proton number
M(H) = mass of hydrogen atom
N = neutron number
M(n) = mass of neutron

BTW, some older textbooks (and radiochemists) may refer to packing
fraction where
M - A
packing fraction = -----
A


Rick

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