Practice Questions

Recall the geometry of $[Ni(CO)_4]$ and $[PtCl_4]^{2-}$ complexes.

Define the term 'coordination number' of a central metal ion.

Evaluate the statement: 'Geometrical isomerism is impossible for tetrahedral complexes.' Justify your conclusion.

Formulate the coordination isomer of $[ ext{Cr(NH}_3)_6][ ext{Co(CN)}_6]$ and justify why it is classified as such.

Define the term 'ligand' in the context of coordination chemistry.

Critique the Valence Bond Theory by explaining two of its major limitations in describing the properties of coordination compounds.

Why is geometrical isomerism not possible in tetrahedral complexes? Analyze the spatial arrangement of ligands.

Describe homoleptic and heteroleptic complexes, providing one example for each.

Design a coordination compound that is expected to exhibit linkage isomerism and justify your choice of metal and ligand.

Solve for the oxidation number of the central metal atom in the coordination entity $K_3[Cr(C_2O_4)_3]$.

Apply IUPAC nomenclature rules to solve for the chemical formula of the compound Iron(III) hexacyanidoferrate(II).

Define an ambidentate ligand and give two examples.

Name a coordination compound used in the treatment of lead poisoning.

Compare the magnetic properties of $[NiCl_4]^{2-}$ (tetrahedral) and $[Ni(CN)_4]^{2-}$ (square planar) by applying the Valence Bond Theory.

Justify, using Crystal Field Theory, why tetrahedral complexes rarely form low-spin configurations.

Explain the difference between a double salt and a complex compound using one example for each.

Identify the central metal ion and its oxidation number in the coordination compound $K_3[Cr(C_2O_4)_3]$.

List the four main postulates of Werner's theory of coordination compounds.

Name the type of isomerism exhibited by the complex $[Co(NH_3)_5(NO_2)]Cl_2$.

Explain the terms 'coordination sphere' and 'counter ions' with reference to the complex $K_4[Fe(CN)_6]$.

A coordination compound has the formula $PtCl_4 \cdot 5NH_3$. When treated with excess $AgNO_3$, one mole of this compound precipitates three moles of $AgCl$. Analyze this observation to determine the structural formula of the complex and the secondary valence of platinum.

Apply Crystal Field Theory to analyze why $[Fe(H_2O)_6]^{3+}$ is strongly paramagnetic, whereas $[Fe(CN)_6]^{3-}$ is weakly paramagnetic.

Analyze and explain why anhydrous copper sulphate ($CuSO_4$) is a white solid, whereas hydrated copper sulphate ($CuSO_4 \cdot 5H_2O$) is blue.

Apply IUPAC rules to provide the systematic name for the coordination compound $[Co(NH_3)_5(CO_3)]Cl$.

Analyze the M-C bond in metal carbonyls to explain the concept of synergic bonding.

Calculate the number of unpaired electrons in the octahedral complex ion $[Mn(CN)_6]^{3-}$.

Contrast the chemical behavior of a double salt, like Mohr's salt $FeSO_4 \cdot (NH_4)_2SO_4 \cdot 6H_2O$, and a coordination compound, like potassium hexacyanidoferrate(II) $K_4[Fe(CN)_6]$, when dissolved in water.

Formulate the structures of all possible stereoisomers for the complex ion $[ ext{Co(en)}_2 ext{Cl}_2]^+$. Justify the existence of each isomer type.

Evaluate the relative thermodynamic stabilities of the complexes $[ ext{Ni(NH}_3)_6]^{2+}$ and $[ ext{Ni(en)}_3]^{2+}$. Justify your reasoning.

Propose a set of simple chemical tests to distinguish between the ionization isomers $[ ext{Co(NH}_3)_5 ext{SO}_4] ext{Br}$ and $[ ext{Co(NH}_3)_5 ext{Br}] ext{SO}_4$.

Propose a reliable method, other than X-ray crystallography, to distinguish between the cis and trans isomers of diamminedichloridoplatinum(II), $[ ext{Pt(NH}_3)_2 ext{Cl}_2]$.

Justify the diamagnetic nature of tetracarbonylnickel(0), $[ ext{Ni(CO)}_4]$, using Valence Bond Theory, considering that the ground state electronic configuration of Ni is $3d^8 4s^2$.

Critique the foundational assumption of Crystal Field Theory that ligands are treated as point charges. Why is this a significant limitation?

Examine the coordination entity $[Co(en)_2Cl_2]^+$ and demonstrate its geometrical and optical isomerism by drawing the structures of all possible isomers.

Design an experimental procedure to determine the formula of a cobalt(III) chloride-ammonia complex, given that its empirical formula is $ext{CoCl}_3 \cdot 5 ext{NH}_3$. Your procedure should allow you to distinguish between possible formulas like $[ ext{Co(NH}_3)_5 ext{Cl}] ext{Cl}_2$ and $[ ext{Co(NH}_3)_5( ext{H}_2 ext{O})] ext{Cl}_3$ (if dissolved in water).

Recall the coordination number of the central metal ion in $[Pt(en)_2Cl_2]^{2+}$.

Explain why geometrical isomerism is not possible in tetrahedral complexes.

Propose a plausible structure for a complex containing Chromium(III), two ethane-1,2-diamine (en) ligands, and two thiocyanate ($ext{SCN}^-$) ligands. Create the systematic IUPAC name for this complex cation, assuming the thiocyanate binds through nitrogen.

Propose a detailed explanation for the observed color difference between an aqueous solution of $[ ext{CoF}_6]^{3-}$ and $[ ext{Co(CN)}_6]^{3-}$, using the principles of Crystal Field Theory.

Calculate the spin-only magnetic moment (in Bohr Magnetons) for the complex ion $[CoF_6]^{3-}$.

Summarize the concept of the chelate effect.

Examine the isomers $[Co(NH_3)_5Br]SO_4$ and $[Co(NH_3)_5SO_4]Br$. Analyze how you would experimentally demonstrate that they are ionisation isomers.

Explain the concept of primary and secondary valences as proposed by Werner, using the example of $[Co(NH_3)_5Cl]Cl_2$.

A solution of $[Ni(H_2O)_6]^{2+}$ is green, but a solution of $[Ni(CN)_4]^{2-}$ is colorless. Analyze this difference by applying Crystal Field Theory.

Evaluate the magnetic properties of $[ ext{Fe(H}_2 ext{O)}_6]^{2+}$ and $[ ext{Fe(CN)}_6]^{4-}$. Calculate the theoretical spin-only magnetic moment for each and justify the difference based on ligand field strength.