The elements of 3d transition series are given as: Sc, Ti, V, Cr, Mn, Fe, Co. Answer the following:
(i) Write the element which shows the maximum number of oxidation states. Give reason.
(ii) Which element has the highest m.p.?

(i) Cr and Mn show the maximum number (six) of oxidation states as they have the maximum number (five) of unpaired electrons in the 3d orbital. (ii) Chromium has the highest m.p. as it has the maximum number of unpaired electrons and forms stronger metallic bonds. (iii) Scandium shows only a +3 oxidation state. (iv) Iron is a strong oxidizing agent in the +3 oxidation state. It readily accepts an electron to form the +2 oxidation state. Iron in the +3 oxidation state can also accept 3 electrons to form the 0 oxidation state.