The energy levels of one-electron ions are given by the equation E_n = (-2.18 aJ) Z^2/n^2 where Z is atomic number, n is the energy level, and aJ is the abbreviation for the unit attojoules. Ionization energy is the energy needed to eject an electron from an atom or ion. Calculate the ionization energy, IE, of the one-electron ion O^7+. The electron starts in the lowest energy level, n = 1.