State any two common chemical properties of a transition element.
Aqueous solutions of cobalt(II) salts contain the complex ion $[\text{Co}(\text{H}_2\text{O})_6]^{2+}$. What is meant by complex ion?
Separate samples of $[\text{Co}(\text{H}_2\text{O})_6]^{2+}$ are each treated with excess aqueous ammonia, excess concentrated HCl and excess aqueous sodium hydroxide, as shown in Fig. 2.1. Complete Table 2.1 to show the reactions of $[\text{Co}(\text{H}_2\text{O})_6]^{2+}$. For every reagent, state the formula of the cobalt species formed, the colour and physical state of the cobalt species formed, and the reaction type.
Explain what is meant by a bidentate ligand.
The complex $\left[\text{Co(H}_2\text{O)}_2(\text{C}_2\text{O}_4)\text{BrCl}\right]^-$ shows stereoisomerism. Complete the three-dimensional diagrams in Fig. 2.2 to display four stereoisomers of $\left[\text{Co(H}_2\text{O)}_2(\text{C}_2\text{O}_4)\text{BrCl}\right]^-$.
State the oxidation state of cobalt in this complex and name a type of stereoisomerism shown.