Complete the electronic configuration for the copper atom and the copper ion in the $+2$ oxidation state. • copper atom: $[\text{Ar}]\ \ldots$ • copper ion in the $+2$ oxidation state: $[\text{Ar}]\ \ldots$
An equilibrium is set up between two copper complex ions in the $+2$ oxidation state: $[\text{Cu(H}_2\text{O})_6]^{2+} + 4\text{Cl}^- \rightleftharpoons [\text{CuCl}_4]^{2-} + 6\text{H}_2\text{O}$ What name is given to the reaction taking place here?
State the colours of these two complex ions. $[\text{Cu(H}_2\text{O})_6]^{2+}$ and $[\text{CuCl}_4]^{2-}$.
State the shape of the $[\text{CuCl}_4]^{2-}$ ion.
Write down the expression for the stability constant, $K_{\text{stab}}$, for this equilibrium.
Copper also forms the complex ions $[\text{Cu(NH}_3)_2(\text{H}_2\text{O})_4]^{2+}$ and $[\text{Cu(en)(H}_2\text{O})_4]^{2+}$ where $\text{en}$ is the bidentate ligand ethane-1,2-diamine, $\text{H}_2\text{NCH}_2\text{CH}_2\text{NH}_2$. $[\text{Cu(H}_2\text{O})_6]^{2+} + 2\text{NH}_3 \rightleftharpoons [\text{Cu(NH}_3)_2(\text{H}_2\text{O})_4]^{2+} + 2\text{H}_2\text{O}$ (equilibrium 1) $[\text{Cu(H}_2\text{O})_6]^{2+} + \text{en} \rightleftharpoons [\text{Cu(en)(H}_2\text{O})_4]^{2+} + 2\text{H}_2\text{O}$ (equilibrium 2) What is the meaning of the term bidentate ligand?
The table gives the stability constants for these two complexes: $[\text{Cu(NH}_3)_2(\text{H}_2\text{O})_4]^{2+}$, $K_{\text{stab}} = 7.94 \times 10^7$ $[\text{Cu(en)(H}_2\text{O})_4]^{2+}$, $K_{\text{stab}} = 3.98 \times 10^{10}$ What do these $K_{\text{stab}}$ values indicate about the relative positions of equilibria 1 and 2?
Nickel forms the complex ion $[\text{Ni(en)}_3]^{2+}$ in which it is surrounded octahedrally by six nitrogen atoms. Name the type of stereoisomerism shown by $[\text{Ni(en)}_3]^{2+}$.
Draw three-dimensional diagrams to show the two stereoisomers of $[\text{Ni(en)}_3]^{2+}$.
Ethane-1,2-diamine is a useful reagent in organic chemistry. Explain how the amino groups in ethane-1,2-diamine enable the molecule to act as a Brønsted-Lowry base.
Write an equation for the reaction of ethane-1,2-diamine with excess hydrochloric acid.
Under certain conditions, ethane-1,2-diamine reacts with ethanedioic acid, $\text{HO}_2\text{CCO}_2\text{H}$, to form the polymer $Z$. Draw the structure of this polymer, $Z$, showing two repeat units.
Name the type of reaction that occurs during this polymerisation.
Polymer $Z$ is an example of a biodegradable polymer. Name a polymer that is non-biodegradable.