Question

If an individual proton has mass 1.007825 amu and an individual neutron has mass 1.008665 amu, and the observed atomic mass of gadolinium-157 is 156.92396 amu, what's its mass defect?

Question options:

A)

–1.38269 amu

B)

–1.35833 amu

C)

1.35833 amu

D)

1.38269 amu

Answer 1

–1.38269 amu

Step-by-step explanation:

There are 64 protons and 93 Neutrons in gadolinium-157

If you multiply the number of protons and neutrons by their individual mass

P= 1.007825 amu * 64 = 64.5008

N= 1.008665 amu * 93 = 93.805845

Then add them together to get 158.306645 as the calculated mass.

Now, Subtract the calculated mass from the observed atomic mass

Δm = 156.92396 amu – 158.306645 amu

Δm = –1.38269 amu is your mass defect

Answer 2

Answer: 1.38269

Step-by-step explanation: