1. The problem statement, all variables and given/known data The question was, you have a Helium ion with one electron in its ground state. Then a second electron is added to the n = 10 level. What effect does the second electron have the first electron that is nearest the nucleus? Is the energy increased or decreased? 2. Relevant equations 3. The attempt at a solution Now I would say the energy would have to be increased, since the first atom is already in its ground state so cant decrease any further. I presume the electrons experience some repulsion from each other, but not sure why this would cause the energy of the first electron to increase.