(a) (i) Draw the shape of one of the d orbitals.

1. (a)(i)Draw the shape of one of the d orbitals.[1]
2. (a)(ii)Complete the following electronic configurations. Ni 1s²2s²2p⁶3s²3p⁶ Ni³⁺ 1s²2s²2p⁶3s²3p⁶[1]
3. (b)(i)Complete the diagram to show how the presence of ligands around an isolated transition metal ion affects the energy of the d orbitals. [Figure: Incomplete diagram showing energy levels for 'isolated transition metal ion', 'octahedral complex', 'tetrahedral complex' and 'degenerate d orbitals' label. Two empty boxes for octahedral and tetrahedral splitting.][1]
4. (b)(ii)Explain why transition metal complexes are coloured.[2]
5. (b)(iii)[Cu(H₂O)₆]²⁺ is pale blue but [Cu(NH₃)₄(H₂O)₂]²⁺ is deep purple-blue. Suggest a reason for this.[1]
6. (c)The diagram shows the visible spectrum of a solution of [V(H₂O)₆]³⁺. [Figure: Absorption spectrum showing absorption vs wavelength (nm), with 'blue', 'green', 'red' regions indicated.] State and explain what colour the solution is.[2]
7. (d)(i)In the presence of chloride ions, [V(H₂O)₆]³⁺ reacts to form a mixture of isomeric octahedral complexes. [V(H₂O)₆]³⁺ + 2Cl⁻ ⇌ [V(H₂O)₄Cl₂]⁺ + 2H₂O Complete the three-dimensional diagrams to show the two isomers of [V(H₂O)₄Cl₂]⁺. [Figure: Two incomplete octahedral diagrams for isomer 1 and isomer 2.][2]
8. (d)(ii)State the type of isomerism shown by isomer 1 and isomer 2 in (i).[1]
9. (e)(i)The complex [V(H₂O)₆]³⁺ also reacts with ethane-1,2-diamine (en), H₂NCH₂CH₂NH₂, to form a mixture of isomeric octahedral complexes. [V(H₂O)₆]³⁺ + 3en ⇌ [V(en)₃]³⁺ + 6H₂O Complete the three-dimensional diagrams to show the two isomers of [V(en)₃]³⁺. You may use N N to represent en. [Figure: Two incomplete octahedral diagrams for isomer 1 and isomer 2.][2]
10. (e)(ii)State the type of isomerism shown by isomer 1 and isomer 2 in (i).[1]
11. (f)(i)The reaction of [Ni(H₂O)₆]²⁺ with aqueous ammonia produces the complex [Ni(NH₃)₆]²⁺. [Ni(H₂O)₆]²⁺(aq) + 6NH₃(aq) ⇌ [Ni(NH₃)₆]²⁺(aq) + 6H₂O(l) Write the expression for Kstab for [Ni(NH₃)₆]²⁺.[1]
12. (f)(ii)[Ni(H₂O)₆]²⁺ also reacts with en to form [Ni(en)₃]²⁺. The values of the stability constants for the two complexes are shown. Kstab [Ni(NH₃)₆]²⁺ = 4.8 × 10⁷ mol⁻⁶ dm¹⁸ Kstab [Ni(en)₃]²⁺ = 2.0 × 10¹⁸ mol⁻³ dm⁹ A solution containing equal numbers of moles of ammonia and en is added to [Ni(H₂O)₆]²⁺. State which complex is produced in the larger amount. Explain your answer.[1]
13. (f)(iii)Adding a limited amount of en to [Ni(H₂O)₆]²⁺ forms the complex [Ni(H₂O)₂(en)₂]²⁺. Suggest the number of possible stereoisomers of [Ni(H₂O)₂(en)₂]²⁺. Explain your answer. You are advised to include three-dimensional diagrams in your answer.[2]

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