Question 1

Which of the following ligands have two potential atoms of attachment (donor atoms)? A) H₂O B) CH₃CH₂NH₂ C) (CH₃)₂NCH₂CH₂NH₂

Accepted Answer

(CH₃)₂NCH₂CH₂NH₂ is a bidentate ligand with two nitrogen atoms as donor atoms.

Question 2

Find the correct name for the complex [Fe(CN)₅(H₂O)]^2-: A) aquapentacyanidoferrate(III) B) aquapentacyanidoiron(III) C) aquapentacyanidoiron(-2)

Accepted Answer

The complex is an anion, so it has a negative charge. The iron ion is in the +3 oxidation state, so the complex is [Fe(CN)₅(H₂O)]^2-. The name of the complex is aquapentacyanidoferrate(III).

Question 3

Suggest the most likely geometry for (i) [FeCl₄]^2- and (ii) [PdCl₄]^2-. A) Both (i) and (ii) are tetrahedral B) (i) is tetrahedral and (ii) is square planar C) (i) is square planar and (ii) is tetrahedral

Accepted Answer

For (i) [FeCl4]2-, iron (Fe) is in a +2 oxidation state, leading to a d^6 configuration which typically forms tetrahedral complexes due to the high spin configuration. For (ii) [PdCl4]2-, palladium (Pd) is in a +2 oxidation state, leading to a d^8 configuration which typically forms square planar complexes, especially for Pd(II) due to its preference for this geometry.

Question 4

For which elements would you expect to find coordination numbers above eight?&#10;A) only for the d block elements&#10;B) for the f block elements&#10;C) both d and f block elements frequently have coordination numbers above 8.

Accepted Answer

The answer of For which elements would you expect to...

Question 5

Which class of ligands can give linkage isomers?&#10;A) bidentate&#10;B) tridentate&#10;C) ambidentate

Accepted Answer

Ambidentate ligands can bind to the central metal atom/ion through two different atoms, allowing for the possibility of linkage isomers.

Question 6

How many isomers are possible for a tetrahedral complex [Ma₂bc]? A) 0 B) 2 C) 4

Accepted Answer

The answer of How many isomers are possible for a...

Question 7

For which of the following cases of octahedral complexes should we consider the possibility of optical isomers? A) A complex with three chelating ligands. B) If the complex has a general formula [Ma₂b₄]. C) If the complex has a general formula [Ma₃b₃] and mer geometry.

Accepted Answer

A complex with three chelating ligands can exhibit optical isomerism because the arrangement of the ligands can lead to non-superimposable mirror images, which is a requirement for optical activity.

Question 8

Amino acids are important chelating ligands that bind to the metal through N and O atoms. Suppose you prepared a square planar platinum complex using D amino acid [Pt(D-AA)₂]. Do you expect a chiral complex?

A) No, because square planar complexes can only have geometrical isomers.
B) Yes, because the amino acid is chiral.
C) No, because the chirality of one amino acid cancels the chirality of the second amino acid.

Accepted Answer

The amino acid is chiral, and the square planar complex can have two different arrangements of the amino acids, resulting in a chiral complex.

Question 9

Which of the following statements is(are) correct?
(i) K_f is a measure of the interaction strength of a ligand relative to the interaction strength of the solvent molecules as a ligand.
(ii) The general trend in successive formation constants is K₁ < K₂ < K₃ < …. < K_n.
(iii) The dissociation constant is inverse of the formation constant.

A) (i) and (iii)
B) (ii)
C) (ii) and (iii)

Accepted Answer

(i) Correct. The notation K_f represents a stepwise formation constant for a ligand binding to a metal ion, comparing the strength of interaction of the ligand to that of solvent molecules, indicating the relative binding affinity.(iii) Correct. The dissociation constant (Kd) is indeed the inverse of the formation constant (Kf), reflecting the equilibrium between the associated and dissociated states of a complex.

Question 10

Find the correct statement:&#10;A) The more donor atoms a ligand has the greater entropic chelation effect.&#10;B) Chelate complexes are favoured only thermodynamically.&#10;C) Chelate effect affects primarily the reaction enthalpy.

Accepted Answer

The chelate effect refers to the enhanced affinity of chelating ligands for a metal ion compared to the affinity of a collection of similar non-chelating (monodentate) ligands for the same metal. The chelate effect is largely entropic because it involves the displacement of more than one ligand by one chelating ligand, leading to an increase in disorder.

Deck 7: An Introduction to Coordination Compounds