JEE Main · 2007 · 29 Apr 2007 · Offline · d and f Block Elements

The actinoids exhibits more number of oxidation states in general than the lanthanoids. This is because

(A)the $5 f$ orbitals are more buried than the $4 f$ orbitals
(B)there is a similarity between $4 f$ and $5 f$ orbitals in their angular part of the wave function
(C)the actinoids are more reactive than the lanthanoids
(D)the $5 f$ orbitals extend further from the nucleus than the $4 f$ orbitals✓ Correct

Answer: (D)

Solution

The actinoids show a wider range of oxidation states than the lanthanoids because their

5 f

orbitals reach comparatively far out from the nucleus. Lying nearer the outside of the atom, the

5 f

electrons are less tightly bound and can join the

6 d

and

7 s

electrons in bonding. The

4 f

orbitals of the lanthanoids are buried more deeply and are well shielded, so they take little part in bonding, which keeps those elements largely in the

+ 3

state.

JEE Main · 2007 · 29 Apr 2007 · Offline · Single correct option

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JEE Main · 2007 · 29 Apr 2007 · Offline · d and f Block Elements

Solution

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