Complete the electronic configuration for a copper atom. $$1s^22s^22p^6\ \ldots$$
Explain why most copper(II) salts appear coloured. Suggest why copper(I) salts are generally white.
Brass is an alloy made from copper and zinc. The reaction below can be used to find the amount of copper in a brass sample: $$2\text{Cu}^{2+}(aq) + 4\text{I}^-(aq) \rightarrow 2\text{CuI}(s) + \text{I}_2(aq)$$ The iodine formed was titrated using thiosulfate ions as follows: $$\text{I}_2(aq) + 2\text{S}_2\text{O}_3^{2-}(aq) \rightarrow 2\text{I}^-(aq) + \text{S}_4\text{O}_6^{2-}(aq)$$ The volume of $0.500\ \text{mol dm}^{-3}$ $\text{S}_2\text{O}_3^{2-}$ solution needed was $28.35\ \text{cm}^3$. Calculate the percentage by mass of copper in the brass sample.
Use standard electrode potential data from the Data Booklet to determine $E^\circ_{\text{cell}}$ for the reaction: $$2\text{Cu}^{2+}(aq) + 4\text{I}^-(aq) \rightarrow 2\text{CuI}(s) + \text{I}_2(aq)$$
Explain how the value of $E^\circ_{\text{cell}}$ calculated in (i) shows that the reaction is unlikely to occur.
Use the Nernst equation to find the electrode potential, $E$, for the $\text{Cu}^{2+}/\text{Cu}^+$ half cell in this experiment.
Copper(I) chloride is also sparingly soluble in water. Suggest why the following reaction does not occur: $$2\text{Cu}^{2+}(aq) + 4\text{Cl}^-(aq) \rightarrow 2\text{CuCl}(s) + \text{Cl}_2(aq)$$
When chloride ions are introduced into a solution containing $\text{Cu}^{2+}(aq)$, the complex ion $[\text{CuCl}_4]^{2-}(aq)$ forms. State the colours of $\text{Cu}^{2+}(aq)$ and $[\text{CuCl}_4]^{2-}(aq)$.
Name the type of reaction that occurs when $[\text{CuCl}_4]^{2-}(aq)$ is formed from $\text{Cu}^{2+}(aq)$.
Write the expression for the stability constant, $K_{\text{stab}}$, of $[\text{CuCl}_4]^{2-}(aq)$. Include the units in your answer.