Complete the electronic configuration for the iron atom. $\text{Fe }\; 1s^2\,2s^2\,2p^6\,\ldots$
In some complexes, the $\text{Fe}^{3+}$ ion has only one unpaired electron in its d orbitals. Using $\uparrow$ and $\downarrow$ to stand for electrons of opposite spins, complete the diagram below to show the d orbital electronic configuration of this $\text{Fe}^{3+}$ ion.
A solution containing a mixture of $\text{Sn}^{2+}\text{(aq)}$ and $\text{Sn}^{4+}\text{(aq)}$ is mixed with a solution containing a mixture of $\text{Fe}^{2+}\text{(aq)}$ and $\text{Fe}^{3+}\text{(aq)}$. Use $E^{\circ}$ data from the Data Booklet to predict the reaction that may occur when the two solutions are combined, and write an equation for the reaction.
Hexaaquairon(III) ions are pale violet. They form a colourless complex with fluoride ions, $\text{F}^-$, equilibrium 1, and a deep-red complex with thiocyanate ions, $\text{SCN}^-$, equilibrium 2. $[\text{Fe(H}_2\text{O)}_6]^{3+} + \text{F}^- \rightleftharpoons [\text{Fe(H}_2\text{O)}_5\text{F}]^{2+} + \text{H}_2\text{O}$ equilibrium 1 $K_{\text{stab}} = 2.0 \times 10^5\,\text{mol}^{-1}\,\text{dm}^3$ $[\text{Fe(H}_2\text{O)}_6]^{3+} + \text{SCN}^- \rightleftharpoons [\text{Fe(H}_2\text{O)}_5\text{SCN}]^{2+} + \text{H}_2\text{O}$ equilibrium 2 $K_{\text{stab}} = 1.0 \times 10^3\,\text{mol}^{-1}\,\text{dm}^3$ Predict and explain the order of colour changes you would see in each of these experiments. • A few drops of KSCN(aq) are introduced into $5\,\text{cm}^3$ of $\text{Fe}^{3+}$(aq), then a few drops of KF(aq) are added. • A few drops of KF(aq) are introduced into $5\,\text{cm}^3$ of $\text{Fe}^{3+}$(aq), then a few drops of KSCN(aq) are added.
What sort of reaction occurs during the experiments in (i)?