A-Level Chemistry: Transition Metals

Transition metal chemistry is the crown of A-level inorganic: complex ions, colour, catalysis and the precise definitions that gatekeep the marks. This quiz covers the whole Year 2 topic.

The definitional questions are strict where the exam is strict: which species actually meet the incomplete-d-subshell definition of a transition metal (Fe³⁺ and Ti³⁺ qualify; d¹⁰ zinc and d⁰ scandium famously do not), and the copper(II) configuration ([Ar]3d⁹ — after losing the 4s electron first), the exception-laden corner of electron structure.

The complex-ion questions build the coordination chemistry toolkit: ligands classified by denticity, EDTA⁴⁻ as the hexadentate archetype, the chelate effect explained properly through the entropy gain of releasing multiple monodentate ligands, and [CuCl₄]²⁻ as the tetrahedral, coordination-number-4 counterexample to the default octahedral picture — driven by chloride's bulk.

Colour is tested at its mechanism: d-orbital splitting, absorption of visible light across the gap, and the full list of changes that alter a complex's colour — ligand identity, oxidation state and coordination number, all three credited. Catalysis distinguishes heterogeneous surface adsorption from homogeneous same-phase catalysis with Fe²⁺ as the aqueous example, and metal-aqua chemistry appears through the brown iron(III) hydroxide precipitate with sodium hydroxide.

The explanations consistently link observation to electronic structure — the register in which every transition-metal exam question is marked.

• Apply the incomplete-d-subshell definition, including the Zn and Sc exclusions
• Write d-block configurations including the Cu exception
• Classify ligands by denticity and explain the chelate effect via entropy
• Explain complex colour through d-orbital splitting and what changes it
• Distinguish heterogeneous from homogeneous catalysis and predict aqua-ion reactions

Aligned to the transition metals content of the DfE A level science subject content as delivered in current specifications: d-block configurations, complex ions and ligands, colour, variable oxidation states, catalysis and metal-aqua chemistry.