Explain ligand substitution reactions.

In the subtopic Complex ions and ligand substitution (A-level only), this AQA A-Level Chemistry 7405 learning objective focuses on explain ligand substitution 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 ligand. Coordinate bond. means a coordinate bond is a type of covalent bond where both electrons in the bond come from the same atom, typically formed between a ligand and a transition metal Avoid the mistake of students often confuse ligand substitution reactions with simple displacement reactions, failing to recognize that ligands are replaced in complex ions rather than just being displaced; instead, to clarify ligand substitution, remember that a ligand is a molecule or ion that donates a pair of electrons to a metal ion to form a coordinate bond. In a ligand substitution reaction, one ligand is replaced by another, maintaining the coordination number of the metal ion. For example, in the reaction [Cu(H2O)6]²⁺ + 4Cl⁻ → [CuCl4]²⁻ + 6H2O, the water ligands are replaced by chloride ions For exam answers, when explaining ligand substitution reactions, clearly define the ligands involved and the nature of the coordinate bonds formed. Use diagrams to illustrate the changes in coordination number and geometry