Interpret colour changes in transition-metal reactions.

In the subtopic Isomerism and redox in transition-metal chemistry (A-level only), this AQA A-Level Chemistry 7405 learning objective focuses on interpret colour changes in transition-metal reactions. It belongs to Transition metals (A-level only), so revision should stay anchored to this exact subtopic rather than drifting into a generic GCSE-level chemistry summary. Approved keywords to use include colour, changes, transition-metal, reactions, interpret. Transition metal. means a d-block element that can form one or more stable ions with an incomplete d subshell, often exhibiting variable oxidation states and coloured compounds Avoid the mistake of students often state that the colour change in transition-metal reactions is due to the presence of the metal ion without specifying the role of ligands; instead, students should explain that the colour change is due to the interaction between the metal ion and the ligands, which affects the d-orbitals and the absorption of specific wavelengths of light For exam answers, when studying transition metal reactions, pay close attention to the colour changes that occur. These changes can indicate the formation of different oxidation states or complex ions