Transition metals are described as elements with partially full d orbitals (or that readily form them). The d-block (groups 3–11) and f-block element elements are among them. Transition metals have a wide range of properties due to their complicated valence shells. Unlike most main group metals, which only have one oxidation state, transition metals have a valence shell structure that allows them to exist in multiple stable oxidation states. Compounds contains lots of transition elements are known for being brightly coloured. The d-orbitals absorb light of various energies as visible light passes through a transition metal complex dissolved in water. A clearly coloured solution is produced when visible light of a certain energy level is not absorbed.