Define what is meant by a transition element.
Compare the melting point and density of iron with those of calcium, an s-block element in the fourth period.
Complete the electronic configuration of an isolated gaseous $\text{Fe}^{2+}$ ion: $1s^2$ ..........
Aqueous $\text{Fe}^{3+}$ ions form coloured complexes. Explain the origin of the colour in transition element complexes.
State the shape of the $[\text{Fe(H}_2\text{O)}_6]^{2+}(aq)$ complex ion.
Write the equation for the reaction between $[\text{Fe(H}_2\text{O)}_6]^{2+}(aq)$ ions and an excess of $\text{CN}^-(aq)$ ions.
Deduce the oxidation states of iron in $[\text{Fe(CN)}_6]^{4-}$ and $[\text{Fe(CN)}_5\text{NO}]^{2-}$.
Define what is meant by a monodentate ligand.
Complete the diagram so that it shows the three-dimensional structure of the $[\text{Fe(CN)}_5\text{NO}]^{2-}$ complex ion.
The two complex ions $[\text{Fe(CN)}_6]^{4-}$ and $[\text{Fe(CN)}_5\text{NO}]^{2-}$ are different colours. Explain why the colours of the two complex ions are different.
Define the term coordination number.
$E$ shows both optical isomerism and cis-trans isomerism. One isomer of $E$ is shown. The $\text{C}_2\text{O}_4^{2-}$ ion is represented as ox. In the boxes, draw three-dimensional diagrams to show the trans isomer of $E$ and the optical isomer of $E$.
$[\text{Fe}(\text{C}_2\text{O}_4)_2\text{Cl}_2]^{4-}$ contains ligands which are anions of ethanedioic acid, $\text{HO}_2\text{CCO}_2\text{H}$. Complete the table to show any observations for the reactions of $\text{HO}_2\text{CCO}_2\text{H}$ with the named reagents. Where no change is seen, write 'none'.