State what is meant by transition element.
The $d$ orbitals in an isolated transition metal ion are degenerate. In complexes, the $d$ orbitals are divided into two energy levels. Complete the diagram to show the arrangement of $d$ orbital energy levels in octahedral complexes and in tetrahedral complexes.
Sketch the shape of two $d$ orbitals: • one $d$ orbital from the lower energy level in an octahedral complex. • one $d$ orbital from the higher energy level in an octahedral complex. Use the axes below.
On the diagram of $\text{edds}^{4-}$, circle every atom that forms a bond with the $\text{Fe}^{3+}$ ion in $[\text{Fe}(\text{edds})]^-$.
$[\text{Fe}(\text{edds})]^-$ is red and $[\text{Fe}(\text{edta})]^-$ is yellow. Explain why these two complexes have different colours.
When $\text{edds}^{4-}$(aq) is added to $\text{Fe}^{3+}$(aq), the following reaction occurs: $[\text{Fe}(\text{H}_2\text{O})_6]^{3+}$(aq) $+$ $\text{edds}^{4-}$(aq) $\rightleftharpoons$ $[\text{Fe}(\text{edds})]^-$$(\text{aq}) + 6\text{H}_2\text{O}$(l). State the type of reaction that occurs.
Write an expression for the stability constant, $K_{stab}$, of $[\text{Fe}(\text{edds})]^-$$(\text{aq})$.
The table gives the stability constant values, $K_{stab}$, for both complexes. Predict which of the $[\text{Fe}(\text{edds})]^-$ and $[\text{Fe}(\text{edta})]^-$ complexes is more stable. Explain your answer with reference to the $K_{stab}$ value for each complex.
When excess $\text{edta}^{4-}$(aq) is added to $[\text{Fe}(\text{edds})]^-$$(\text{aq})$, the following equilibrium is set up: $[\text{Fe}(\text{edds})]^-$$(\text{aq}) + \text{edta}^{4-}$(\text{aq}) $\rightleftharpoons$ $[\text{Fe}(\text{edta})]^-$$(\text{aq}) + \text{edds}^{4-}$(\text{aq})$. Calculate the equilibrium constant, $K_c$, for this equilibrium, using the $K_{stab}$ values given.