Question

What is the mass defect of lithium? Assume the following: Atomic number of lithium = 3 Atomic mass of lithium = 7.0144 atomic mass units. Mass of 1 proton = 1.0073 atomic mass units. Mass of 1 neutron = 1.0087 atomic mass units.
(A)0.0043 atomic mass units
(B)0.0423 atomic mass units
(C)3.0219 atomic mass units
(D)4.0348 atomic mass units
(E)7.0567 atomic mass units

Answer 1

3 protons x 1.0073amu = 3.022 
4 neutrons x 1.0087amu = 4.035 

mass = 7.0567amu 
mass defect = 7.0567 - 7.0144 = 0.0423amu.....B with your mass of Li