Complete the electronic configuration of the copper(II) ion: $1s^2 2s^2 2p^6 \; \ldots$
State the colour of the solutions containing the following ions: • $[\text{Cu(H}_2\text{O)}_6]^{2+}(aq)$ • $[\text{CuCl}_4]^{2-}(aq)$
Octahedral complexes of $\text{Cu}^{2+}$ with different ligands can have different colours. Explain why.
Copper(I) and silver(I) salts are colourless. Suggest why.
Consider these two equilibria and their associated data values at $298\,\text{K}$: Equilibrium $1$: $\text{AgBr}(s) \rightleftharpoons \text{Ag}^+(aq) + \text{Br}^-(aq)$, with $K_{sp} = 5.0 \times 10^{-13}\,\text{mol}^2\,\text{dm}^{-6}$. Equilibrium $2$: $\text{Ag}^+(aq) + 2\text{NH}_3(aq) \rightleftharpoons [\text{Ag(NH}_3)_2]^+(aq)$, with $K_{stab} = 1.7 \times 10^7\,\text{mol}^{-2}\,\text{dm}^6$. For equilibrium $1$, the equilibrium constant is the solubility product, $K_{sp}$, of $\text{AgBr}(s)$. For equilibrium $2$, the equilibrium constant is the stability constant, $K_{stab}$, for formation of $[\text{Ag(NH}_3)_2]^+(aq)$.
Calculate the solubility of $\text{AgBr}$ at $298\,\text{K}$ in $\text{mol dm}^{-3}$.
Use Le Chatelier’s principle for equilibria $1$ and $2$ to suggest why $\text{AgBr}(s)$ dissolves in concentrated $\text{NH}_3(aq)$.
Use equilibria $1$ and $2$ to build an equation for the reaction of $\text{AgBr}(s)$ with concentrated $\text{NH}_3(aq)$. This is equilibrium $3$.
Write an expression for the equilibrium constant of equilibrium $3$, $K_{eq3}$, in terms of $K_{sp}$ for equilibrium $1$ and $K_{stab}$ for equilibrium $2$.
Define the term standard electrode potential, $E^\circ$.
Complete and label the diagram to show how the standard electrode potential, $E^\circ$, of $\text{Ag}^+(aq)/\text{Ag}(s)$ could be measured under standard conditions.
Use the Data Booklet to label the diagram in (e)(i) so that it shows: • which electrode is positive, • the direction of electron flow in the external circuit when a current flows.