(i) Transition metals have the ability to adsorb many other substances on their surface and activate them as a result of chemisorption. Transition metals also exhibit a variety of oxidation states, and can change oxidation states relatively easily. This makes transition metals and their compounds good catalysts.

(ii) Eo values are indicative of the stability of the oxidized form of the element. The lower the E∘ value, more stable the oxidized form of the element. Mn2+ with a half filled d-subshell (d5) is stable, so Mn is easily oxidized to Mn2+, making the Eo value negative. Cu2+ with a partially filled d subshell (d9) is not stable, and is relatively easily reduced to element form. This makes its E∘ value positive.

(iii) The electronic configurations of actinoids show irregularities because the energies of their 5f,6d, and 7s-orbitals are close to each other. Electrons can easily move between these subshells.