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Question #44854
The Question
Evaluate the following four statements regarding the chemistry of d-block and f-block elements. Assign the given numerical value to each statement if it is CORRECT. If it is INCORRECT, assign it a value of 0.
Statement I (Value = 1): Due to the combined effects of lanthanoid and relativistic contractions, the absolute size of the octahedral voids in a 5d transition metal lattice (e.g., \ce{W}) is smaller than that in its 3d counterpart (e.g., \ce{Cr}).
Statement II (Value = 2): Actinoids exhibit a wider range of oxidation states than lanthanoids because the 5f orbitals are less deeply buried than the 4f orbitals, and the energy gap between 5f, 6d, and 7s orbitals is smaller than that between 4f, 5d, and 6s orbitals.
Statement III (Value = 4): In the non-stoichiometric hydride \ce{PdH_x}, the hydrogen atoms occupy the octahedral voids of the FCC palladium lattice, causing a measurable expansion of the unit cell parameter.
Statement IV (Value = 8): If a 4d and a 5d transition metal of the same group crystallize in the same lattice type and have identical atomic radii due to the lanthanoid contraction, the ratio of their theoretical densities is exactly equal to the ratio of their atomic masses.
Calculate the sum of the values of the CORRECT statements.
Options
- A.
10
- B.
11
- C.
14
- D.
15
Check Your Answer
Correct Answer
Step-by-Step Solution
Explanation
How the Examiner Thinks
Exception_Exposure
Learn to identify edge cases and boundary exceptions that JEE examiners hide in math problems.
Concepts Behind This Question
d-orbital contraction|Interstital Compound Formation|Actinoid Oxidation State Variety
Why This Question Is Tricky
Common Mistakes
The question tests the precise structural consequences of the lanthanoid contraction and f-block electronic configurations.
The primary trap (Statement I) preys on the common misconception that 'contraction' implies 5d metals are smaller than 3d metals, whereas it only cancels the expected size increase from 4d to 5d ().
Additionally, it tests the specific interstitial site occupancy in Palladium hydrides (octahedral, not tetrahedral) and the exact reason for Actinoid oxidation state variety (5f being less shielded/buried than 4f), acting as a comprehensive discriminator for elite students.
Quick Facts About This Question
Question Information
| Subject | Chemistry |
| Chapter | D and F Block Elements - Class 12 |
| Concept | d-orbital contraction |
| Difficulty | 8 |
| Cognitive Load | 7 |
| Target Solve Time | 160 sec |
| Access | Free |