Question

which atom has multiple oxidation states and forms an ion that is colored when in solution

Answer 1

Hi, the atom I can say that has multiple oxidation states and forms an ion that is colored when in solution is copper metal.

Copper has two oxidation since copper exists as copper (II) and copper (I) and  when the ions are in the solution they are normally colored.

Most of the atoms which are colored are those that belong to the transition metals. They are colored because their d orbitals are not fully filled with electrons and thus allowing for d-d transition.