Which two first-row $d$-block elements have just one electron in the $4s$ orbital of their neutral atoms?
The $d$ orbitals in an isolated transition metal atom or ion are said to be degenerate. What does degenerate mean?
Sketches of the shapes of the atomic orbitals from the $d$ subshell are shown. In an octahedral complex, the $d$ orbitals split into two sets at different energy levels. On the diagram below, place an ‘H’ in the box under each orbital at the higher energy level.
The reaction scheme below shows several reactions of $\text{Cu}^{2+}(\text{aq})$. Suggest the formula for each of the following: A, B, C.
State the colours of the following solutions: solution of B; solution of C.
Name the type of reaction that takes place when C is heated with copper. Deduce the role of the copper metal in this reaction.
When the solution containing the complex $[\text{CuCl}_2]^-$ is added to water, CuCl precipitates. CuCl is white because it does not absorb visible light. Explain why CuCl does not absorb visible light.
The complex ion $[\text{Cr(H}_2\text{O})_6]^{3+}$ has colour because it absorbs visible light. The absorption spectrum for $[\text{Cr(H}_2\text{O})_6]^{3+}$ is shown. Suggest the colour of this complex ion. Explain your answer.