JEE Main · 2011 · 10 Apr 2011 · Offline · d and f Block Elements

In context of the lanthanoids, which of the following statements is not correct ?

(A)All the members exhibit +3 oxidation state
(B)Because of similar properties the separation of lanthanoids is not easy.
(C)Availability of 4 f electrons results in the formation of compounds in +4 state for all the members of the series.✓ Correct
(D)There is a gradual decrease in the radii of the members with increasing atomic number in the series.

Answer: (C)

Solution

All lanthanoids show the

+ 3

state, their close similarity does make separation difficult, and lanthanoid contraction steadily shrinks their radii across the series, so those statements are correct. The flawed one claims that the availability of

4 f

electrons lets every member form

+ 4

compounds; in fact only a few, such as cerium, praseodymium, terbium and dysprosium, reach

+ 4

, so that statement is not correct.

JEE Main · 2011 · 10 Apr 2011 · Offline · Single correct option

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JEE Main · 2011 · 10 Apr 2011 · Offline · d and f Block Elements

Solution

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