1. The problem statement, all variables and given/known data Compare the energies of the 1s, 2s, 3s and 3p orbitals for both the HE and He+. For He assume that one electron is always in the 1s orbital. State any other assumptions you have made 2. The attempt at a solution I think: He can be either 1s1 2s1 or 1s2 He+ has to be 1s1. For He 1s2, the 1s orbital has a lower energy than in the case of He+ and since there is a greater shielding, this allows the 2s, 3s and 3p to rise in energy. Hence these have a higher energy than in He+. For He1s1 2s1 is basically the same thing, only that now 1s1 has a higher energy than 1s2 but still lower than He+ and 2s1 has a lower energy than in the other cases. Thanks!!