Final answer:
Manganese (Mn) shows the maximum number of oxidation states among the elements Sc, Ti, V, Cr, Mn, Fe, Co because it can exist in +2, +3, +4, +6, and +7 states, with the +7 state being the highest. This is due to the multiple unpaired d-electrons in manganese.
Step-by-step explanation:
The element from the 3d transition series that shows the maximum number of oxidation states is Manganese (Mn). Manganese has observed oxidation states of +2, +3, +4, +6, and +7. The possibility for multiple oxidation states in transition metals is due to the fact that they have closely spaced energy levels for the ns and (n-1)d electrons. In manganese, the availability of multiple unpaired electrons in the d-orbital allows for a variety of electron removal or sharing possibilities, leading to a range of oxidation states.
The exceptional variety of stable oxidation states allows manganese to form many compounds and to participate in redox (reduction-oxidation) reactions, which is key to its ubiquity in biochemical and industrial processes. The oxidation state +7 is the highest for manganese, occurring in permanganate (MnO4-), which indicates that manganese can lose a total of 7 electrons from the s and d orbitals.