Complete the table by giving the total number of unpaired electrons in the $3d$ and $4s$ orbitals for each isolated gaseous atom: $\text{Cr}$, $\text{Mn}$ and $\text{Fe}$.
On heating, solid potassium manganate(VII), $\text{KMnO}_4$, breaks down to manganese(IV) oxide, potassium manganate(VI) and a colourless gas. Write an equation for this reaction.
Explain where the colour in transition element complexes comes from.
Give the formulae of precipitate A, complex ion B and compound C shown in the reaction scheme of $[\text{Cu(H}_2\text{O)}_6]^{2+}$.
Name a suitable reagent for reaction 3.
Give an equation for reaction 4.
State two visual observations that occur 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 $\text{Cl-Pt-Cl}$ bond angle.
Cis-platin is an effective anti-cancer drug. Describe how cis-platin works in this role.
Because cis-platin can produce side effects, nedaplatin has been developed. Nedaplatin can be made from cis-platin, $\text{Pt(NH}_3)_2\text{Cl}_2$, by substituting the two chloride ion ligands with one bidentate ligand, as shown. Suggest the structure for nedaplatin.