Define the term transition element.
Complete Table 5.1 by giving the geometry, the coordination number of copper, and one bond angle for each of the two complex ions $[\text{Cu(H}_2\text{O)}_6]^{2+}$ and $[\text{CuCl}_4]^{2-}$.
In an isolated $\text{Cu}^{2+}$ ion, the $d$-orbitals are all degenerate. In a complex ion such as $[\text{Cu(H}_2\text{O)}_6]^{2+}$, the $d$-orbitals are non-degenerate. Define degenerate and non-degenerate in this context.
Explain why the two complex-ion solutions in Table 5.1 have different colours.
Explain what is meant by the term bidentate.
Three stereoisomers have the formula $[\text{Cu(C}_2\text{O}_4)_2(\text{H}_2\text{O})_2]^{2-}$. Complete the three-dimensional diagrams to show these three stereoisomers.
Stereoisomers 1, 2 and 3 exhibit two distinct types of isomerism. Name these two types of isomerism. For each type, identify the pair of stereoisomers that shows it.
A solution contains $3.70\text{ g}$ of $\text{Na}_2[\text{Cu}(\text{C}_2\text{O}_4)_2(\text{H}_2\text{O})_2]$ dissolved in $100\text{ cm}^3$ of solution. A $25.0\text{ cm}^3$ portion of this solution is warmed and then oxidised by $0.0100\text{ mol dm}^{-3}$ acidified potassium manganate(VII). The redox equation is shown. $5\text{C}_2\text{O}_4^{2-} + 2\text{MnO}_4^- + 16\text{H}^+ \rightarrow 10\text{CO}_2 + 2\text{Mn}^{2+} + 8\text{H}_2\text{O}$. Calculate the least volume of $0.0100\text{ mol dm}^{-3}$ acidified potassium manganate(VII) needed to oxidise all of the ethanedioate ions, $\text{C}_2\text{O}_4^{2-}$, in the $25.0\text{ cm}^3$ sample. Show all your working. $[M_r:\ \text{Na}_2[\text{Cu}(\text{C}_2\text{O}_4)_2(\text{H}_2\text{O})_2],\ 321.5]$
Copper(II) nitrate, $\text{Cu(NO}_3)_2$, and barium nitrate, $\text{Ba(NO}_3)_2$, both decompose on heating. Copper(II) nitrate decomposes at a lower temperature than barium nitrate. Suggest a reason for this difference. Explain your answer.