(a) Members of second and third transition series exhibit similar atomic radii. Explain. (b) Account for the following: (i) Transition metals and their many compounds act as good catalysts. (ii) Actinoids has greater tendency to form complexes in comparison to Lanthanoids.

Explain why transition metals and their many compounds act as good catalyst.

Assign reasons for the following : (i) Transition metals and many fo their compounds act as good catalyst. (ii) Transition metals generally from coloured compounds.

Explain giving a suitable reason for each of the following : (i) Transition metals and their compounds are generally found to be good catalysts. (ii) Metal-metals bonding is more frequent for the 4d and the 5d series of transitions metals than that for the 3d series.

(a) How does permanganate solution react with Fe(II) ions? Write balanced ionic equations for the reaction. (b) Why do transition metals and many of their compounds act as good catalysts?

Assing the reason for the following : (i) Transition metals exhibit enthalpy of atomisation. (ii) Transition metals form interstitial compounds .

Assing the reason for the following : (i) Transition metals generally form coloured compounds. (ii) Manganese exhibits highest oxidation state of +7 among the 3d series of transition elements.

Assign reasons for the following : (i) The enthalpies of atomisation of transition elements are high. (ii) The transition metals and many of their compounds act as good catalyst. (iii) From element to element the actinoid contraction is greater than the lanthanoid contraction. (iv) The E^(@) value for the Mn^(3+)//Mn^(2+) couple is much more positive than that for Cr^(3+)//Cr^(2+) . (v) Scandium (Z = 21) does not exhibit variable oxidation states and yet it is regarded as transition element.

How would you account for the following? (l) Transition metals exhibit variable oxidation states. (ii) Zr (Z = 40) and Hf (Z = 72) have almost identical radii. (iii) Transition metals and their compounds act as catalyst.

How would you account for the following : (i) Many of the transition elements are virtually the same as those of the corresponding members of the second series. (iii) There is a greater range of oxidation states among the actinoids than among the lanthanoids.