What is the nuclear binding energy in joules for an atom of lithium? assume the following: mass defect = 6.9986235 × 10-29 kilograms. use e = mc2, with c = 3 × 108 m/s. 6.3 × 10-12 joules 0.6352 × 10-8 joules 6.3 × 10-8 joules 21.124 × 10-21 joules