d block questions

Give reasons for the following questions related to transition elements:
1. Transition metals form alloys with other transition metals easily.
2. Melting points of transition metals increase up to the middle of the series
and then decrease.
3. Transition metals and their compounds are good catalysts.
4. Zn, Cd and Hg are softer and volatile metals.
5. Cr and Cu exhibit exceptional electronic configurations.
6. Transition metals have high melting points.
7. Transition metals compounds are mostly coloured.
8. Sc3+ and Zn2+ are colourless in aqueous solutions.
9. Transition metals exhibit variable oxidation states.
10. Transition metal series exhibit fewer oxidation states at their extreme ends. (Sc, Ti, Cu)
11. Density of zinc is lower than that of copper.
12. Transition metals have high enthalpy of atomisation.
13. Generally speaking, the enthalpies of atomisation and melting points transition
metals of 3d, 4d and 5d series increase steadily down the group
14. Transition metals and their compounds show paramagnetic behaviour.
15. Hydrated copper sulphate is blue where as anhydrous copper sulphate is white.
16. The magnetic moments of the transition metals increase up to the middle of the series
and then decrease.
17. Transition metals generally form complex compounds.
18. Transition metals form interstitial compounds.
19. The third ionisation enthalpies of Mn & Zn are quite high in comparison to Fe.
20. Zn has little tendency to form complexes.
21. Zn, Cd and Hg are not considered as true transition metals.
22. [Ti(H2O)6]3+ is coloured while [Sc(H2O)6]3+ is colourless.
23. Mn2+ compounds are more stable than Fe2+ compounds towards oxidation to +3 state.
24. The decrease in atomic radius in the case of any d-series is not as large as that in
period 2 or 3.
25. A transition metal exhibits higher oxidation states in oxides and fluorides.
26. The d1 configuration is very unstable in ions of d-Block elements.
27. Scandium(II) is virtually unknown.
28. The magnetic moment of Co3+ is higher than that of Co2+.
29. The lowest oxide of transition metal is basic, the highest is acidic.
30. The densities of post-lanthanoid elements are very high.
31. The atomic sizes of corresponding elements of 4d and 5d series are almost the same.
32. La3+ and Lu3+ are colourless while rest of lanthanoids are coloured in the solid
as well as in aqueous state.
33. The first-ionisation enthalpies of the 5-d transition elements are higher than those of
the 4-d metals.
34. Cu+ is diamagnetic whereas Cu2+ is paramagnetic.
35. The ionisation enthalpy of Hf (6th period) is higher than that of Zr (5th period).
36. The most common oxidation state of lanthanoids is +3. However cerium and europium form additional oxidation states of +4 and +2 respectively.
37. Ce4+ is a good oxidant.
38. Eu2+ is a good reducing agent.

II. Describe the large scale preparation of:
1. Potassium dichromate from chromite ore(FeCr2O4).
2. KMnO4 manufactured from pyrolusite.
III. Write the chemical reactions involved.
1. Acidified potassium dichromate with (a) KI solution (b) FeSO4 solution.
2. Acidified potassium permanganate with (a) oxalate solution (b) Sn2+ solution.
3. Pr + H2O
4. Ce + N2 heated
5. Lu + O2
IV. Compare the chemistry of actinoids with that of the lanthanoids with special reference to:
1. electronic configuration
2. oxidation state
3. atomic sizes
4. chemical reactivity.
V. What is lanthanoid contraction? How would you account for it?
What are its important consequences?
VI. Short Questions:
1. What are transition elements?
2. What is misch-metal?
3. Which is more stable – Mn2+ or Mn4+?
4. What are coinage metals?
5. Write the outer shell configuration of inner transition metals.
6. Calculate the magnetic moment of Mn2+.
7. Draw the structures of , Cr2O72- and CrO42-
8. Name the metal with the highest melting point.
9. Name the actinoid with no 5f electron.
10. Name the lanthanoid with the maximum paramagnetism.
11. What are the uses of lanthanoids?
12. What are transuranic elements?