Question

Calculate the mass defect for the isotope thorium-234

Answer 1

Answer:1.85864 amu

Explanation:

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Answer 2

Mass defect is defined as the difference or discrepancy between the mass of the nucleons and the mass of the nucleus. the nucleons involved are the protons and neutrons. 
mp  = 1.6727 x 10-24 g = 1.007316 amumn = 1.6750 x 10-24 g = 1.008701 amu
mTh 234 = 234 g/mol = 234 amu

Th234 (protons = 90; neutrons = 144)
mass defect = mp*90 + mn *144 - 234
mass defect = 1.911384 amu