Answer:
11.98661
Step-by-step explanation:
1. add up the masses of each proton and of each neutron that make up the nucleus,
2. subtract the actual mass of the nucleus from the combined mass of the components to obtain the mass defect.
1.007825 + 1.008665 = 2.01649
14.0031 - 2.01649 = 11.98661