mass defect = mass of constituents - mass of atom
N has 7p and 9n
proton mass ~ 1.00728 amu
neutron mass ~ 1.00866 amu
electron mass ~ 0.000549 amu
Nitrogen mass ~ 14.003074 amu
mass defect = (7*1.00728)-(7*1.00866)-(7*0.000549) - 14.003074
= 0.11235amu
convert to energy, the binding energy = 1.68x10^-11 J
