Nickel forms complexes.

1. (a)(i)Give the formula and charge of the tetrahedral complex formed by Ni atoms with carbon monoxide molecules. Carbon monoxide is a monodentate ligand. This is complex E. E =[1]
2. (a)(ii)Give the formula and charge of the octahedral complex formed by Ni2+ ions with ethanedioate ions. This is complex F. F =[2]
3. (a)(iii)Identify which complex, E or F, exists as a mixture of two stereoisomers and the type of stereoisomerism involved. The complex which exists as a mixture of two stereoisomers is The type of stereoisomerism involved is[1]
4. (b)(i)Cadmium forms complexes with methylamine, CH3NH2, and 1,2-diaminoethane, en. The values of the stability constants, Kstab, of these complex ions are given in Table 6.1. Explain, by reference to its structure, why CH3NH2 acts as a monodentate ligand.[1]
5. (b)(ii)Some Cd2+(aq) is added to a solution containing equal concentrations of CH3NH2 and en. Predict which of the two complexes in Table 6.1 forms at the higher concentration. Explain your answer. complex that forms at the higher concentration explanation[1]
6. (b)(iii)Complete the expression for the Kstab of [Cd(CH3NH2)4]2+.[1]

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