Question: how much energy is required to ionize a ground state h2 molecule into h2+?
Answer: (Chemists typically use joules, while physicists use electron volts.) For a hydrogen atom, composed of an orbiting electron bound to a nucleus of one proton, an ionization energy of 2.18 × 10−18 joule (13.6 electron volts) is required to force the electron from its lowest energy level entirely out of the atom.