The oxidation number of the central atom in a complex is defined as the charge it would carry if all the ligands are removed along with the electron…

The oxidation number of the central atom in a complex is defined as the charge it would carry if all the ligands are removed along with the electron pairs that are shared with the central atom. Similarly the charge on the complex is the sum of the charges of the constituent parts i.e. the sum of the charges on the central metal ion and its surrounding ligands. Based on this, the complex is called neutral if the sum of the charges of the constituents is equal to zero. However, for an anion or cationic complex, the sum of the charges of the constituents is equal to the charge on the coordination sphere. Based on the above information, answer the following questions :

What is the secondary valence of Co in $\displaystyle \left[\mathrm{Co}\left(\mathrm{NH}_{3}\right)_{4} \mathrm{Cl}_{2}\right]^{+}$?

What type of isomerism is shown by the complex $\displaystyle \left[\mathrm{Cr}\left(\mathrm{H}_{2} \mathrm{O}\right)_{6}\right] \mathrm{Cl}_{3}$ and $\displaystyle \left[\mathrm{Cr}\left(\mathrm{H}_{2} \mathrm{O}\right)_{5} \mathrm{Cl}\right] \mathrm{Cl}_{2} \cdot \mathrm{H}_{2} \mathrm{O}$ ?

Write the electronic configuration of $\displaystyle \mathrm{d}^{4}$ ion on the basis of crystal field theory when

$\displaystyle \Delta_{0}<\mathrm{P}$

$\displaystyle \Delta_{0}>\mathrm{P}$

Find the oxidation state and coordination number of the central metal ion in $\displaystyle \left[\mathrm{Co}\left(\mathrm{H}_{2} \mathrm{O}\right)(\mathrm{CN})(\mathrm{en})_{2}\right]^{2+}$