Complete the table to show how many unpaired electrons are present in the $3d$ and $4s$ orbitals of each isolated gaseous atom: Cr, Mn and Fe.
On heating, solid potassium manganate(VII), $\text{KMnO}_4$, breaks down to give manganese(IV) oxide, potassium manganate(VI) and a colourless gas. Construct an equation for this reaction.
Explain why transition element complexes are coloured.
The reaction scheme shows several reactions of $[\text{Cu(H}_2\text{O)}_6]^{2+}$. Write the formulae of precipitate A, complex ion B and compound C.
Identify a reagent suitable for reaction 3.
Write the equation for reaction 4.
Describe two visual observations seen during reaction 4.
Platin, $\text{Pt(NH}_3)_2\text{Cl}_2$, is a neutral platinum(II) complex. Explain why $\text{Pt(NH}_3)_2\text{Cl}_2$ carries no charge.
$\text{Pt(NH}_3)_2\text{Cl}_2$ shows cis-trans isomerism. Draw the structure of trans-platin. State its shape and the Cl-Pt-Cl bond angle.
Cis-platin is an effective anti-cancer drug. Describe how cis-platin acts in this role.
Because cis-platin can cause side effects, nedaplatin has been developed. Nedaplatin can be made from cis-platin, $\text{Pt(NH}_3)_2\text{Cl}_2$, by replacing the two chloride ion ligands with one bidentate ligand as shown. Suggest the structure of nedaplatin.