This question has me all confused. I'll post it below, it's really asking me to compare Li^++ and hydrogen in terms of energy levels, radius and spectrum of electrons.

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.

If anyone knows the answer it would be great!