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Metals — SQA National 5 Chemistry — SQA National 5 Chemistry Revision Notes & Topical Questions
5 min read 4 parts Lesson 1 of 5
Part 1 of 2Reactivity series and extraction of metals
- Reactivity seriesK > Na > Ca > Mg > Al > Zn > Fe > Sn > Pb > (H) > Cu > Ag > Au.
- Methods of extraction:
- Heat alone
- For unreactive metals low in the series (Ag, Au, Pt, Hg).
- Example: heating silver oxide decomposes it: 2Ag2O(s) → 4Ag(s) + O2(g).
- Heating with carbon or carbon monoxide
- For intermediate metals (Zn, Fe, Sn, Pb, Cu).
- Carbon acts as a reducing agent: 2Fe2O3 + 3C → 4Fe + 3CO2.
- Electrolysis of molten ore
- For highly reactive metals above carbon (K, Na, Ca, Mg, Al).
- Requires large electrical energy.
- Heat alone
Part 2 of 2Electrochemical cells and redox
1Simple electrochemical cell4 points
- Two different metals connected by an external circuit and immersed in an electrolyte (conducts charge via mobile ions).
- A salt bridge (ion bridge) completes the circuit between two half-cells, allowing ions to move and balance electrical charge.
- Electrons flow through the external wires from the more reactive metal to the less reactive metal.
- Voltage ruleThe further apart the two metals are in the electrochemical series, the larger the voltage produced.
2Redox half equations (OIL RIG)3 points
- OxidationLoss of electrons by the more reactive metal: Zn(s) → Zn2+(aq) + 2e-.
- ReductionGain of electrons by the less reactive metal ion: Cu2+(aq) + 2e- → Cu(s).
- Overall redox equationZn(s) + Cu2+(aq) → Zn2+(aq) + Cu(s).
Key terms
| Term | Meaning |
|---|---|
| Electrochemical series | A list of metals arranged in order of their ability to donate electrons (reactivity). |
| Electrolyte | An ionic solution or molten salt that conducts electricity via the movement of free ions. |
| Salt bridge | A porous strip soaked in electrolyte connecting two half-cells to complete the electrical circuit. |
| Reduction | The gain of electrons by a chemical species during a redox reaction. |
Avoid these mistakes
- Stating electrons flow through the salt bridge — electrons only flow through external metal wires;
- only ions move through the salt bridge.
- Stating electrons flow through the salt bridge — electrons only flow through external metal wires;
- Reversing the electron flow — electrons always flow from the metal higher in the reactivity series to the metal lower down.
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🌳 Student Search Tree & Frequently Asked Exam Questions: metals
Step-by-step problem-solving guide, mark scheme criteria, and experimental error analysis curated by Dr. Khaled Dabour (DABOURHUB).
1. Identify all given values and convert non-standard units, 2. State the primary formula or physiological/chemical principle, 3. Calculate to 3 significant figures and clearly state units.
Avoid confusing independent vs dependent variables in practical questions. In calculation questions, double-check percentage change formula: (change / original) × 100.
Where can I find metals past paper questions by topic with the mark scheme?
On DABOURHUB every metals question is grouped by syllabus point and shown with the mark-scheme wording, so you can see exactly which sentence earns the mark instead of scrolling through whole year papers.
What is the most common metals exam question and why do students lose marks on it?
The repeated pattern on IGCSE papers is a short stem that asks you to apply metals and then justify it with a command word (explain, suggest, compare). Marks are lost by stating the fact without linking it back to the wording of the question, so each metals item here is written as a full-mark answer.
Is there an alternative to Save My Exams or Physics and Maths Tutor for metals?
Yes: the metals notes, topical questions and MCQ quizzes on this site follow the same syllabus headings as the official specification, and they open straight from the search result with no download step.
How do I revise metals in two weeks before the exam?
Three passes: read the metals notes once, then do the topical questions and mark them against the mark scheme, then redo only the ones you missed. The quiz on the page gives instant feedback so the third pass takes minutes rather than an evening.