The d-and f-Block Elements Mock Test – Class 12 Chemistry

1. A claim states, “The oxidation state of a transition-metal ion is always equal to the number of its remaining electrons.” The most suitable evaluation is:

2. Complete reaction of of with in acidic medium requires:

3. Oxidation of uranium from to , where uranium is , involves:

4. Use the interaction described below. A ligand approaches a metal ion and forms a coordinate bond. The electron pair used in this bond is ordinarily:

5. During oxidation of to sodium chromate and iron(III) oxide, the changes in oxidation state are:

6. A lanthanoid metal forms of the oxide . If the same mass of metal reacts completely with water according to

the molar mass of the metal and the amount of hydrogen formed are:

7. A ligand stabilises an actinoid in a high oxidation state more effectively than it stabilises the uncomplexed ion in solution. The most reasonable interpretation is:

8. Palladium is unusual among the commonly discussed transition elements because its ground-state configuration is written as:

9. Radioactivity in the actinoid series is described by the statement:

10. A reaction is performed in a strongly alkaline solution, but the product equation is written with as the permanganate reduction product. The most likely diagnosis is:

11. A mixture supplies of electrons through oxidation of . The remaining electrons needed to reduce of dichromate are supplied by iodide ions. The amount of iodide required is:

12. A neutral lanthanoid atom has electrons in , , and subshells. During formation of its common tripositive ion, the electrons are generally removed in the order:

13. A solution of is used in acidic, neutral, and strongly alkaline reactions. Its normalities in these media are respectively:

14. A mixture contains only and . Chemical analysis shows that the mixture contains of copper. Using and , the amounts of and , respectively, are:

15. An actinoid atom forms a ion, but its radioactive behaviour remains. This observation shows that:

16. Use the graph description below. The vertical axis represents melting point and the horizontal axis runs across a transition series. Curve P rises toward a broad central high region and then falls irregularly near the end. Curve Q decreases smoothly from the first element to the last. Curve R remains horizontal, while Curve S has its only maximum at the end. The most realistic curve is:

17. Assertion: Some lanthanoids show relatively stable or oxidation states in addition to the dominant state.
Reason: Formation of , , or configurations can provide enhanced stability.

18. The oxidation states of the transition metals in , , and are respectively:

19. The half-reaction representing electrolytic conversion of manganate into permanganate is:

20. The expected radius order for iron species in comparable environments is:

21. The pair in which both species are diamagnetic is:

22. A learner says, “Because actinoid compounds show greater covalency, every actinoid compound must be a neutral molecular substance.” The best evaluation is:

23. A transition metal X forms , , and . Experiments show that neutralises acids, reacts with both acids and alkalis, and forms an oxoacid with water. The observations are best explained by:

24. is effective in the oxidation of because vanadium can:

25. Assertion: The spin-only magnetic-moment value may differ from an experimentally measured magnetic moment.
Reason: The spin-only expression neglects orbital contributions and other interactions that may influence the observed moment.

26. Match the configuration fragment in Column I with the most suitable interpretation in Column II.

The appropriate matching is:

27. Two lanthanoid ions have configurations and . Assuming electrons occupy the seven orbitals according to Hund’s rule, their numbers of unpaired electrons are respectively:

28. Which safety statement is most appropriate when comparing potassium dichromate and potassium permanganate?

29. Examine the oxidation-state and configuration data below.

The consistent rows are:

30. A learner states, “A non-stoichiometric interstitial compound is merely an uncontrolled mixture with no organised metal lattice.” The best evaluation is:

31. Match each species in Column I with its configuration in Column II.

The appropriate matching is:

32. Assertion: Standard potentials across the first transition series do not form a smooth monotonic sequence.
Reason: Atomisation, successive ionisation, and hydration contributions all vary from one element to another.

33. Adjacent lanthanoids generally resemble one another chemically because they:

34. An element is classified operationally as a transition element when it has:

35. For a -orbital splitting energy , an increase in corresponds to absorption of light with:

36. commonly behaves as an oxidising species in aqueous solution because it tends to:

37. Assertion: The variation in first ionisation enthalpy across a transition series is generally less dramatic than that across a typical main-group period.
Reason: Added electrons provide increasing shielding that partly offsets the rise in nuclear charge.

38. A bar graph represents moles of electrons accepted per mole of oxidant under four conditions:
Case P: acidified
Case Q: neutral-medium
Case R: strongly alkaline
Case S: acidified
Arrange the bar heights in decreasing order:

39. The initial decrease in atomic radii across a transition series is mainly caused by:

40. Two ions of the same metal have radii and in the same coordination environment. If the larger ion is , the percentage decrease in radius on forming the smaller ion is:

41. An element X has atomic number . After representing the first electrons by , its remaining electrons follow the ordinary first-series filling pattern. The configuration and group of X are:

42. Acid is added under suitable conditions to a green manganate solution. A purple solution and a brown solid appear. The products responsible for these observations are respectively:

43. Arrange the following ions in increasing order of the number of unpaired electrons, using the ordinary free-ion configurations:

44. In the spin-only expression , the missing number is:

45. Consider the following statements about interstitial compounds.
Statement I: They are often harder than the parent metal.
Statement II: Many retain metallic conductivity.
Statement III: Their compositions must always correspond to exact small whole-number ratios.
Statement IV: Small atoms such as , , , and may occupy the interstitial sites.
The valid statements are:

46. The configurations and are supplied. These data show that copper is:

47. Four unknown sets of elements are described below. Set P shows progressive filling of , set Q shows progressive filling of , set R shows progressive filling of , and set S shows progressive filling of . The two -block sets are identified as:

48. Equal-mass samples of transition metals X and Y have densities and , respectively. Together, the two samples occupy . The mass of each sample and the sample occupying the larger volume are:

49. and the manganese centre in are both . Their contrasting colours are best explained by the fact that:

50. Assertion: Early actinoids generally show a wider range of oxidation states than later actinoids.
Reason: With increasing nuclear charge, the electrons become more tightly held and less readily available for bonding.