Draw the structures of optical isomers of ${\left[{\mathrm{PtCl}}_2{\left(\mathrm{en}\right)}_2\right]}^{2+}$.

Indicate the types of isomerism exhibited by the following complex and draw the structures for these isomers.

$\left[\mathrm{Co}{\left(\mathrm{en}\right)}_3\right]{\mathrm{Cl}}_3$

Write the number of ions in the solution of the following complex:

${\mathrm{K}}_4\left[\mathrm{Fe}{\left(\mathrm{CN}\right)}_6\right]$

Write the number of ions in the solution of the following complex:

$\left[\mathrm{Ag}{\left({\mathrm{NH}}_3\right)}_2\right]\mathrm{Cl}$