Mass Defect

[MrDMD83]

1. The problem statement, all variables and given/known data

For lead N=210 Z=82 Pb (atomic mass = 209.984163 u) obtain each of the following:
(a) The mass defect in atomic mass units
u
(b) the binding energy (in MeV)
MeV
(c) the binding energy per nucleon (in MeV)
MeV


2. Relevant equations



3. The attempt at a solution

a) 82 x 1.6726e-27 kg + 128 x 1.6749e-27 kg= 3.515e-25 kg

3.515e-25kg x 1u/1.6605e-27= 211.708

211.708-209.984163= 1.72u but it says my answer is wrong.

[MrDMD83]

Nevermind. I forgot to initially subtract the mass of the 82 electrons from the mass of entire atom.