Why does the ionization energy of Ca+ greataer than K even tho they have the same amount of e-

why does Na have a relatively simple atomic spectrum while Cr has a very complex one?

With K the ionization energy is that required to pull away the outside electron. For Ca^+, the energy required to pull away the outside electron is LARGER because it is pulling the electron away from a positively charged ion. Obviously, it is easier to pull an electron away from a neutral ion as compared to pulling it away from a positively charged ion.