d and f BLOCK ELEMENTS MCQ Quiz: GKFix - Bridge of Knowledge

Question 6

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Why do the complexes [Ti(H2O)6]^3+ and [V(H2O)6]^3+ have different colors in aqueous solution?

Because Ti and V are different metals.
Because they have different charges.
Because H2O is a ligand.
Because Ti^3+ (d^1) and V^3+ (d^2) have different numbers of d-electrons, leading to different d-orbital occupancy and different crystal field splitting energies, absorbing different wavelengths of light.

Question 7

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Why do the third ionization enthalpies of Fe, Co, and Ni show a relatively steady increase compared to the more irregular pattern seen for earlier transition metals?

Because Fe, Co, and Ni are metals.
Because they have higher atomic numbers.
Because removing the third electron from Fe^2+ (d^6), Co^2+ (d^7), and Ni^2+ (d^8) involves removing an electron from increasingly filled d-orbitals, without disrupting particularly stable configurations like d^5 or d^10.
Because they are located at the end of the series.

Question 8

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Why do the complexes [Ni(CO)4] and [Ni(CN)4]^2- have different geometries?

Because CO and CN- are different ligands.
Because they have different charges.
Because Ni has different oxidation states.
Because the different ligands (CO vs CN-) and the different oxidation states of Ni (0 vs +2) result in different numbers of d-electrons and different ligand field strengths, favoring different geometries.

Question 9

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Why do the first row transition metals generally form fewer stable compounds with very high coordination numbers (e.g., CN > 6) compared to second and third row transition metals?

Because first row metals are less reactive.
Because first row metals have fewer d-electrons.
Because first row metals are lighter.
Because the smaller size of first row metals makes it sterically difficult to accommodate a large number of ligands around the central metal ion.

Question 10

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Why do the atomic orbitals of 5d elements contract compared to 4d elements, despite having an additional electron shell?

Because 5d elements are heavier.
Because the nuclear charge increases.
Because 5d elements are metals.
Because relativistic effects become significant for elements with high atomic numbers, causing the 5d orbitals to shrink in size.

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