Answer:
Mass defect = - 0.060238 amu
Explanation:
To calculate the mass defect:
1. add up the masses of each proton and of each neutron that make up the nucleus,
Berylium 9 has;
4 protons = 4 * 1.00728 amu = 4.02912 amu
5 Neutrons = 5 * 1.00866 amu = 5.0433 amu
Sum = 9.07242 amu
2. subtract the actual mass of the nucleus from the combined mass of the components to obtain the mass defect.
Mass defect = Actual Mass - Combined mass
Mass defect = 9.012182 amu - 9.07242 amu
Mass defect = - 0.060238 amu
