Would like to see if i've understood this question somewhat. :-) 1. The problem statement, all variables and given/known data A doubly ionised Lithium atom (Li^++) has two of its normal complement of electrons removed. The energy levels of the remaining single electron ion are closely related to those of the neutral Hydrogen atom - since the nuclear charge of Lithium is +3 compared to +1 for Hydrogen. Assuming the Bohr model for the atoms: (a) How are the energy levels of Li^++ ion related to neutral Hydrogen? Estimate values if possible. (b) How is the radius of the Li^++ ion in the ground state related to neutral hydrogen in the ground satte? Estimate values if possible. (c) How would the spectrum of the Li^++ ion be related to neutral Hydrogen. 2. Relevant equations None given. But i think E = 13.6 x Z^2/n^2 is used in part a ? 3. The attempt at a solution (a) I think that the energy levels would be the same since they both have one electron in their shell. (b) The radius of the Li^++ iom would be smaller than that of the neutral hydrogen as the protons and neutrons in the nucleus of the Li^++ would have stronger neutostatic forces and thus will be held more tightly. (c) The spectrum would be similar as they both consist of one electron in their shell and thus only one electron would be ionised.