Transition Metals | Edexcel A-Level Chemistry (9CH0)
Transition Metals
- 123 questions
- 9 subtopics
- Paper 1: advanced inorganic and physical chemistry
- Paper 1 and Paper 3
Covers what makes an element a transition metal, complex ions and their shapes, why the complexes are coloured, ligand exchange, the chemistry of the individual metals, and their catalytic behaviour..
It covers electron configuration and what makes a transition metal, complex ions, ligands and the colour of transition metal ions, coordination number, monodentate ligands and the shapes of complexes, bidentate and multidentate ligands, and ligand exchange, vanadium and chromium chemistry, reactions with sodium hydroxide and ammonia, cobalt and copper complexes, ligand exchange, amphoteric behaviour and the chelate effect and transition metals as catalysts.
Sample questions from Transition Metals
Answer each one closed book first, then open the answer.
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Electron configuration and what makes a transition metal
State the electronic configuration of copper.
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[Ar] 3d¹⁰ 4s¹ -
Complex ions, ligands and the colour of transition metal ions
State a characteristic property of transition metal ions in solution.
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They form coloured ions in solution. -
Coordination number, monodentate ligands and the shapes of complexes
Explain why ammonia acts as a monodentate ligand.
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Ammonia has a lone pair on the nitrogen atom that can form one dative bond to a metal ion. -
Bidentate and multidentate ligands, and ligand exchange
Define a multidentate ligand.
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A ligand that forms more than two dative bonds to the central metal ion. -
Vanadium and chromium chemistry
When vanadium is reduced from +5 to +4 using zinc in acidic conditions, why does this reduction occur?
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The Zn²⁺/Zn couple has a more negative standard electrode potential than the V(V)/V(IV) couple, making the reduction feasible. -
Reactions with sodium hydroxide and ammonia
Explain why the green precipitate formed when Fe²⁺(aq) reacts with ammonia does not dissolve in excess ammonia.
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Fe(OH)₂ does not undergo ligand exchange with ammonia, so the precipitate is insoluble in excess NH₃(aq) and remains unchanged. -
Cobalt and copper complexes
What happens when excess sodium hydroxide solution is added to Cu²⁺(aq)?
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No change occurs; the pale blue precipitate remains. -
Ligand exchange, amphoteric behaviour and the chelate effect
What happens when [Cu(H₂O)₆]²⁺ reacts with concentrated HCl, and what colour change is observed?
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[CuCl₄]²⁻ forms, with a colour change from pale blue to yellow.
The 9 subtopics
One subtopic is one session. Work down the list.
| Subtopic | What it covers | Questions |
|---|---|---|
| Electron configuration and what makes a transition metal | Recall questions on the d-block configurations, on the exceptions at chromium and copper, on which elements are excluded, and on variable oxidation states. | 14 |
| Complex ions, ligands and the colour of transition metal ions | Ligands, dative bonds and complex ions, why transition metal ions are coloured through d-orbital splitting and d-d transitions, why d⁰ and d¹⁰ ions are colourless, and how a change of oxidation number, ligand or coordination number changes the colour. | 12 |
| Coordination number, monodentate ligands and the shapes of complexes | Coordination number, water, hydroxide ions and ammonia as monodentate ligands, octahedral complexes with 90° bond angles, tetrahedral complexes with chloride ions at 109.5°, and square planar complexes such as cisplatin. | 12 |
| Bidentate and multidentate ligands, and ligand exchange | Why cisplatin is supplied as a single isomer, bidentate ligands such as ethane-1,2-diamine, the multidentate ligand EDTA⁴⁻, haemoglobin as an iron(II) complex, and the ligand exchange by which carbon monoxide displaces oxygen. | 10 |
| Vanadium and chromium chemistry | The colours of vanadium in its +5, +4, +3 and +2 oxidation states, using E° values to explain reduction by zinc in acid, reducing dichromate(VI) to Cr³⁺ and Cr²⁺ with zinc, oxidising Cr³⁺ with alkaline hydrogen peroxide, and the chromate(VI) and dichromate(VI) equilibrium. | 14 |
| Reactions with sodium hydroxide and ammonia | The hydroxide precipitates Cr³⁺, Fe²⁺, Fe³⁺ and Co²⁺ give with sodium hydroxide and ammonia and which dissolve in excess, the oxidation of Fe(OH)₂ in air, and Core Practical 12 preparing tetraamminecopper(II) sulfate, with its purpose, equation, method, safety and yield. | 24 |
| Cobalt and copper complexes | Cobalt(II) and copper(II) ions with sodium hydroxide and ammonia and which precipitates dissolve in excess, ligand exchange to deep blue [Cu(NH₃)₄(H₂O)₂]²⁺ in excess ammonia and its equation, and the colours of [Cu(H₂O)₆]²⁺ and the copper hydroxide precipitate. | 14 |
| Ligand exchange, amphoteric behaviour and the chelate effect | Defining ligand exchange and amphoteric behaviour, Cr(OH)₃ dissolving in excess hydroxide, the colour of the copper ammine complex, ligand exchange with concentrated hydrochloric acid to give [CuCl₄]²⁻ and [CoCl₄]²⁻, why the coordination number falls from six to four, and the chelate effect explained by the entropy change. | 12 |
| Transition metals as catalysts | Heterogeneous and homogeneous catalysis by transition metals, vanadium(V) oxide in the contact process, adsorption, reaction and desorption in a catalytic converter, Fe²⁺ catalysing the reaction between I⁻ and S₂O₈²⁻, and Mn²⁺ as an autocatalyst in the reaction of MnO₄⁻ with C₂O₄²⁻. | 11 |
How the guide is worked
Answering a question from memory stores it far better than reading the answer again. The guide runs that as a fixed procedure on one subtopic at a time, about twenty minutes a session.
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Step 1 · Closed book
Cover the answers. Work through one subtopic and write down what you can. Leave blanks where you have nothing.
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Step 2 · Open book
Go back to the top. Read each printed answer and write it out in full, including the ones you had right.
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Step 3 · Closed book again
Same questions, same order, from memory. The gap between pass one and pass three is the session result.
Read the full method, the return schedule and the research behind it.
Nearby topics
Edexcel A-Level Chemistry Active Recall Guide
Every topic, not just this one. 1,534 questions with their answers.