Explain why transition elements show variable oxidation states.
Sketch the form of a $3d_{z^2}$ orbital in Fig. 4.1.
Separate samples of $[\text{Cu(H}_2\text{O})_6]^{2+}(aq)$ are treated with excess solution A and, separately, with excess solution B. With solution A, $[\text{Cu(H}_2\text{O})_6]^{2+}(aq)$ undergoes a precipitation reaction. With solution B, $[\text{Cu(H}_2\text{O})_6]^{2+}(aq)$ undergoes ligand substitution. Suggest a possible identity for solution A and for solution B. Include the relevant observations and the formula of the copper-containing product in each case.
Solutions containing the $[\text{Ag(NH}_3)_2]^+$ complex are colourless. Explain why this complex has no colour.
Fig. 4.2 shows two bidentate ligands. Explain what is meant by a bidentate ligand.
Ruthenium(III) ions, $\text{Ru}^{3+}$, form an octahedral complex, $[\text{Ru(dpys)}_2\text{Cl}_2]^+$, with dpys and chloride ions as the ligands. This complex shows the same sort of stereoisomerism as $[\text{Ru(NH}_3)_4\text{Cl}_2]^+$, but it also displays a different kind of stereoisomerism. Complete the three-dimensional diagrams in Fig. 4.3 to show the three separate stereoisomers of $[\text{Ru(dpys)}_2\text{Cl}_2]^+$. The dpys ligand can be shown as $\mathrm{N{-}N}$.
State the different kinds of stereoisomerism shown by $[\text{Ru(dpys)}_2\text{Cl}_2]^$.
Deduce which stereoisomers in (e)(i) are non-polar. Explain your answer.