Question

What is the electron configuration for the transition metal ion(s) in each of the following compounds?

Pt forms +2 and +4 oxidation states in compounds.

Short answer

Each of the compounds containing central metal ion with definite oxidation state.

Step-by-step solution

a) Identification of central metal atom

Co is the only transition element as a central metal atom.

Determining the oxidation state of central metal atom:

${\left({\mathrm{NH}}_4\right)}_2\left[\mathrm{Fe}{\left({\mathrm{H}}_2\mathrm{O}\right)}_2{\mathrm{Cl}}_4\right]\to {\left[\mathrm{Fe}{\left({\mathrm{H}}_2\mathrm{O}\right)}_2{\mathrm{Cl}}_4\right]}^{2-}$

Neutral ligand is water

Anionic ligandhas charge -1.

is the oxidation state of central atom Fe

So,

$\begin{array}{l}X+2\times 0+4\times (-1)=-2\\ X=+2\end{array}$

Determining electronic configuration:

$\begin{array}{l}\mathbf{Fe}\mathbf{=}\mathbf{\left[}\mathbf{Ar}\mathbf{\right]}\mathbf{3}{\mathbf{d}}^{\mathbf{6}}\mathbf{4}{\mathbf{s}}^{\mathbf{2}}\\ {\mathbf{Fe}}^{\mathbf{2}\mathbf{+}}\mathbf{=}\mathbf{\left[}\mathbf{Ar}\mathbf{\right]}\mathbf{3}{\mathbf{d}}^{\mathbf{6}}\end{array}$${\left({\mathrm{NH}}_4\right)}_2\left[\mathrm{Fe}{\left({\mathrm{H}}_2\mathrm{O}\right)}_2{\mathrm{Cl}}_4\right]\to {\left[\mathrm{Fe}{\left({\mathrm{H}}_2\mathrm{O}\right)}_2{\mathrm{Cl}}_4\right]}^{2-}$

b) Identification of central metal atom

Fe is the only transition element as a central metal atom.

Determining the oxidation state of central metal atom:

$\left[Co{\left(N{H}_3\right)}_2{\left(N{H}_{2}C{H}_{2}C{H}_{2}N{H}_2\right)}_2\right]I_2\to {\left[Co{\left(N{H}_3\right)}_2{\left(N{H}_{2}C{H}_{2}C{H}_{2}N{H}_2\right)}_2\right]}^{2+}$

Neutral ligands are${\mathrm{NH}}_2-{\mathrm{CH}}_2-{\mathrm{CH}}_2-{\mathrm{NH}}_2$and${\mathrm{NH}}_3$

X is the oxidation state of central atom Co

So,

$\begin{array}{l}X+2\times 0+2\times 0=+2\\ X=+2\end{array}$

Determining electronic configuration:

c) Identification of central metal atom

Ta is the only transition element as a central metal atom.

Determining the oxidation state of central metal atom:

${\mathrm{Na}}_2\left[{\mathrm{TaF}}_7\right]\to {\left[{\mathrm{TaF}}_7\right]}^{2-}$

Anionic ligandhas charge -1.

is the oxidation state of central atom Ta

So,

$\begin{array}{l}X+7\times (-1)=-2\\ X=+5\end{array}$

Determining electronic configuration:

$\begin{array}{l}\mathrm{Ta}=\left[\mathrm{Xe}\right]6{\mathrm{s}}^{2}4{\mathrm{f}}^{14}5{\mathrm{d}}^3\\ {\mathrm{Ta}}^{5+}=\left[\mathrm{Xe}\right]4{\mathrm{f}}^{14}\end{array}$

d) Identification of central metal atom

Pt is the only transition element as a central metal atom.

$\left[\mathrm{Pt}{\left({\mathrm{NH}}_3\right)}_4{\mathrm{I}}_2\right]\left[{\mathrm{PtI}}_4\right]$