Draw the outline of a $d$ orbital.
Explain the meaning of the term transition element.
Transition elements are able to form complex ions containing ligands. Name the bonding type present between a ligand and a transition element.
Write down the formulae of two iron oxides. State the oxidation number of iron in each one.
$\text{CO}$ and $\text{CN}^-$ are both monodentate ligands. Complete the table for the two complexes below.
Transition element complexes may show stereoisomerism. $[\text{Cu(H}_2\text{O})_4(\text{NH}_3)_2]^{2+}$ and $\text{Pt(NH}_3)_2\text{Cl}_2$ exhibit the same kind of isomerism. Name this type of isomerism.
Complete the 3D diagrams of the two isomers for $[\text{Cu(H}_2\text{O})_4(\text{NH}_3)_2]^{2+}$ and $\text{Pt(NH}_3)_2\text{Cl}_2$.
Copper is able to form complexes with ammonia and $en$, $\text{H}_2\text{NCH}_2\text{CH}_2\text{NH}_2$, as illustrated.\n\n$[\text{Cu(H}_2\text{O})_6]^{2+}(aq) + en(aq) \rightleftharpoons [\text{Cu(H}_2\text{O})_4(en)]^{2+}(aq) + 2\text{H}_2\text{O}(l)$, $K_{\text{stab}} = 3.98 \times 10^{10}$ (equilibrium 4)\n\n$[\text{Cu(H}_2\text{O})_6]^{2+}(aq) + 2\text{NH}_3(aq) \rightleftharpoons [\text{Cu(H}_2\text{O})_4(\text{NH}_3)_2]^{2+}(aq) + 2\text{H}_2\text{O}(l)$, $K_{\text{stab}} = 5.01 \times 10^{7}$ (equilibrium 5)\n\nWrite an expression for the stability constant, $K_{\text{stab}}$, for equilibrium 5. Give its units.
The standard entropy change, $\Delta S^{\circ}$, for equilibrium 4 is $+23\,\text{J K}^{-1}\text{mol}^{-1}$ and for equilibrium 5 is $-8.4\,\text{J K}^{-1}\text{mol}^{-1}$. Give an explanation for this difference with reference to both equilibria.
Of the three copper complexes in equilibria 4 and 5, state which copper complex is the most stable and explain your answer.