Class 9 Science Chapter 3 Metals and Non-Metals Previous Year Questions (2020–2025)

Reading the NCERT chapter twice doesn't guarantee confident answers under exam pressure. Past paper questions train your brain to *recognize what examiners ask* and *how to structure answers* to earn full marks. For Chapter 3, examiners consistently ask about the reactivity series (and its order), defining corrosion with one real-world example, comparing metal and non-metal properties in table format, and writing two balanced equations for metal displacement reactions. When you solve 5–10 PYQs, your pattern recognition sharpens: you'll know that 'Write the chemical reaction for copper and oxygen' always expects a balanced equation *and* the state symbols (s), (g), (aq). You'll spot that 3-mark questions always pair a concept (e.g., 'What is corrosion?') with an application ('How does rust form on iron?'). Past papers also reveal time management: most students waste 3–4 minutes on a 1-mark question because they haven't practiced terse, direct answers. By drilling these 13 questions, you'll write faster, lose fewer marks to vague explanations, and build the reflexive confidence that raises final scores by 5–8 marks. At cbsetutor.ai, we track which PYQs trip up the most students and flag them here so your revision is laser-focused.

One-mark questions on Metals and Non-Metals focus on recall and simple distinctions. Examiners test your vocabulary (defining corrosion, reactivity), your memory of the reactivity series order, and quick property identification. Here are the five most common 1-mark PYQs: **Q1: Which of the following is a non-metal that conducts electricity? A) Sulphur B) Phosphorus C) Graphite D) Nitrogen Answer: C) Graphite** — Reason: Graphite is an allotrope of carbon (non-metal) with delocalized electrons that allow electrical conduction. Sulphur, phosphorus, and nitrogen are insulators. **Q2: Define corrosion. Answer: Corrosion is the slow chemical process in which metals react with oxygen, water, or other substances in the environment to form metal compounds, often causing deterioration of the metal.** — This definition appears in 4 out of 5 recent papers. Add one example ('rust on iron') for bonus clarity. **Q3: Arrange Zn, Cu, Mg in order of increasing reactivity. Answer: Cu < Zn < Mg** (or: Copper is least reactive, magnesium is most reactive) — The reactivity series question is almost guaranteed. Memorize the top 10: K, Na, Ca, Mg, Al, Zn, Fe, Ni, Sn, Pb, H, Cu, Hg, Ag, Au. **Q4: Which property is typical of metals? A) Poor conductor of heat B) Malleable C) Non-lustrous D) Brittle Answer: B) Malleable** — Malleability (ability to be hammered into sheets) and ductility (ability to draw into wires) are defining metal traits. **Q5: Name the process by which metals are extracted from their ores. Answer: Metallurgy (or: Extraction of metals / Reduction of metal oxides)** — Examiners often ask this in one mark; don't overthink — just name the field or broad process.

Three-mark questions require two components: a concept explanation (1.5 marks) and one worked example or comparison (1.5 marks). They test deeper reasoning than 1-mark but stop short of 5-mark derivations. **Q1: Explain the difference between a metal and a non-metal based on their physical properties. Give one example of each.** Answer: *Metals* have high melting points, are lustrous, malleable, ductile, and good conductors of heat and electricity. Example: Iron. *Non-metals* have low melting points (except graphite), are non-lustrous, brittle, and poor conductors of heat and electricity. Example: Sulphur. This question tests whether you can construct a comparison table mentally — write it as two short paragraphs, one per substance, using parallel structure. **Q2: What is the reactivity series? Arrange the following in decreasing order of reactivity: Fe, Cu, Al, Zn.** Answer: The reactivity series is an arrangement of metals in order of their tendency to lose electrons and form positive ions (increasing order: least reactive to most reactive). Decreasing reactivity: Al > Zn > Fe > Cu Aluminium is most reactive (loses electrons easily), copper is least reactive (resists oxidation). This ordering predicts displacement reactions: Al will displace Fe from FeSO₄, but Cu cannot displace Zn from ZnSO₄. **Q3: Write the balanced chemical equations for (i) copper burning in air, (ii) the reaction between magnesium and oxygen.** Answer: (i) 2Cu + O₂ → 2CuO (black solid forms at high temperature) (ii) 2Mg + O₂ → 2MgO (intense white light and white solid; highly exothermic) Bonus insight: Mg reacts vigorously even at room temperature with air; Cu requires heating — a practical clue to their reactivity difference. **Q4: Why is iron coated with zinc to prevent corrosion? Name this process.** Answer: Iron is highly reactive and corrodes quickly when exposed to moisture and oxygen. Zinc (less reactive than iron in dry conditions, forms a protective oxide layer) is coated on iron as a protective barrier. This process is called *galvanization*. The zinc layer also sacrifices itself (sacrificial anode), preventing iron from rusting. **Q5: What happens when a piece of copper is heated strongly in air? Write the equation and describe the colour change.** Answer: 2Cu + O₂ → 2CuO The copper metal (reddish-brown) turns black when heated, as a layer of copper(II) oxide forms on its surface. This demonstrates the combination of a metal with non-metal (oxygen).

Five-mark questions demand multi-step reasoning, balanced equations, and applications. They often combine two sub-topics (e.g., reactivity series + extraction method, or chemical properties + corrosion prevention). **Q1: (a) Describe the process of extraction of metals in general terms. (b) Why can carbon reduce the oxides of metals below it in the reactivity series, but cannot reduce the oxides of metals above it? (c) Write the balanced equation for the extraction of iron from its ore using carbon monoxide.** Answer: (a) Metal extraction typically involves three steps: 1. Ore mining and concentration (removing impurities). 2. Reduction of metal oxide to pure metal using a suitable reducing agent (carbon, carbon monoxide, or electricity). 3. Refining to increase purity. (b) Carbon's reducing ability depends on its position in the reactivity series. Carbon lies between Al and Zn in the reactivity series. It can displace metals *below* it (Cu, Fe, Zn) from their oxides because carbon is more reactive than these metals and 'pulls away' their oxygen. Metals *above* carbon (Al, Mg, Ca) are so reactive that they hold oxygen too tightly; carbon cannot compete for the oxygen — instead, these metals are reduced by electrolysis or displacement by more reactive metals. (c) 3Fe₂O₃ + 8CO → 6Fe + 8CO₂ Or, showing it stepwise: Fe₂O₃ + 3CO → 2Fe + 3CO₂ Carbon monoxide removes oxygen from iron ore, producing pure molten iron. **Q2: (a) What is corrosion? (b) Write the chemical equation for the rusting of iron. (c) Describe two methods to prevent the rusting of iron. (d) Why does aluminium not corrode like iron, even though it is more reactive?** Answer: (a) Corrosion is a slow oxidation process in which a metal reacts with oxygen, water, or acidic/basic substances in its environment, forming a compound that weakens or destroys the metal. (b) 4Fe + 3O₂ + 2H₂O → 4FeO·OH (or written as Fe₂O₃·3H₂O) Rust forms only in the presence of *both* oxygen and water; dry iron does not rust. (c) Two prevention methods: 1. *Galvanization*: Coat iron with zinc. The zinc oxide layer (ZnO) is impermeable, blocking water and oxygen from reaching the iron. Zinc also acts as a sacrificial anode, corroding instead of iron. 2. *Painting or oiling*: A physical barrier (paint, grease, or oil) prevents water and oxygen from reaching the metal surface. (Other valid methods: alloying with stainless steel, using rust-inhibiting paints, electroplating.) (d) Although aluminium is more reactive than iron, it *resists corrosion* because it forms a thin, dense, transparent layer of aluminum oxide (Al₂O₃) on its surface within microseconds of exposure to air. This oxide layer is *impermeable* and self-healing (new Al₂O₃ forms if the layer is scratched). Iron's corrosion product (rust, FeO·OH) is porous and crumbly, allowing water and oxygen to penetrate further, accelerating corrosion. **Q3: (a) Explain why metals are good conductors of electricity. (b) Write balanced equations for the reaction of (i) sodium with water, (ii) magnesium with dilute hydrochloric acid. (c) What would you observe in each case?** Answer: (a) Metals possess delocalized valence electrons (often described as an 'electron sea') that move freely throughout the metal lattice. These mobile electrons conduct electric current when a potential difference is applied. Non-metals lack such mobile electrons, hence poor conductivity. (b) Equations: (i) 2Na + 2H₂O → 2NaOH + H₂↑ (ii) Mg + 2HCl → MgCl₂ + H₂↑ (c) Observations: (i) Sodium reacts vigorously: the metal melts into a ball due to heat released, skitters across the water surface, and a yellowish flame may be seen (exothermic reaction). (ii) Magnesium reacts: vigorous effervescence (bubbling) occurs as hydrogen gas is produced; the solution becomes warm; magnesium ribbon gradually dissolves. — These reactions demonstrate chemical reactivity and the hierarchy in the reactivity series (Na > Mg; both displace H from water/acid).

The CBSE Science curriculum underwent rationalization in 2023–24, and further revisions may emerge for 2026–27. Based on recent trend analysis, examiners are shifting focus in three ways: **1. Emphasis on Real-World Applications & Case Studies** Examiners are moving away from purely theoretical questions ('Define corrosion') toward contextualized scenarios ('A ship's hull is corroding. Explain which corrosion prevention method is most cost-effective and why'). Expect more questions linking metals/non-metals to industries (construction, electronics, aerospace) and sustainability (recycling metals, reducing mining waste). **2. Graphical & Data Interpretation** Recent papers include short tables (melting points of metals, reactivity data) or graphs (corrosion rates over time) and ask students to *interpret* them. Practice reading data and drawing conclusions (e.g., 'Which metal corrodes fastest in saltwater?' followed by a table showing corrosion mass loss over months). **3. Reduced Rote Learning, Increased Problem-Solving** The trend away from memorizing long reactivity series is evident. Instead, examiners provide a partial series or a set of displacement reactions and ask you to *deduce* the order. For example: 'Given that Al displaces Fe from Fe₂O₃, Fe displaces Cu from CuO, and Cu does not displace Zn from ZnSO₄, arrange Al, Fe, Cu, Zn in reactivity order.' This tests logical reasoning, not memory. **4. More Balanced Equation Practice Across Diverse Reactions** While core reactions (metals + oxygen, metals + acids) remain, examiners are testing non-metals too (S + O₂ → SO₂, P₄ + 5O₂ → P₄O₁₀). Ensure you're comfortable balancing equations beyond the classic metal combustions. **Recommendation**: Practice 2–3 papers per week focusing on case-study questions and data tables, not just definition recall. This positions you for the evolved assessment style.

In a 90-minute Science exam, allocate ~25–30 minutes to Chapter 3 (depending on total weightage). Here's a battle-tested strategy: **Pre-Exam (1 Week Before)** 1. Write the reactivity series on a card and drill it daily (K, Na, Ca, Mg, Al, Zn, Fe, Ni, Sn, Pb, H, Cu, Hg, Ag, Au). Do not rely on looking it up; it must be automatic. 2. Practice 5 past papers, timing yourself on each. Mark 1-mark questions should take 30–45 seconds; 3-mark questions, 2–3 minutes; 5-mark questions, 4–6 minutes. 3. For every balanced equation you write, check it using the atom-count method (count atoms on left and right; ensure they match). **During Exam** 1. **Scan the chapter first** (2 minutes): Skim all questions to identify which are 1, 3, or 5 marks. Don't start with the hardest. 2. **Answer 1-mark questions first** (8 minutes): These are confidence-builders. Direct answers, no elaboration. If it asks for a definition, give it in one clear sentence + one example. 3. **Tackle 3-mark questions next** (12 minutes): Always split your answer into two parts: *concept* (e.g., 'Corrosion is…') and *application* (e.g., 'Rust forms when iron meets water and oxygen because…'). Write a short paragraph for each part, not a long essay. 4. **Attack 5-mark questions last** (8–10 minutes): Identify sub-parts (a), (b), (c). If stuck on (a), skip it and earn marks on (b) and (c) — come back to (a) if time permits. For equations, always include state symbols; for explanations, use cause-and-effect language ('Because A is reactive, it strips oxygen from B, yielding…'). 5. **Leave 2 minutes for review**: Scan your answers for spelling errors in compound names (CuO, not CuOO; FeO·OH, not FEO·OH) and basic arithmetic (balanced equation atom counts). **Common Exam Mistakes to Avoid** - Writing 'Mg burns in O₂' but forgetting the equation (lose 1–2 marks). - Confusing the reactivity order (saying 'Cu is more reactive than Al'); double-check by memorizing the top 8. - Forgetting state symbols in equations (e.g., writing 'Cu + O₂ → CuO' instead of '2Cu + O₂ → 2CuO(s)'). - Over-explaining 1-mark answers (e.g., 'Corrosion is when metal meets oxygen and they dance together and form compounds…'). Examiners want crisp, textbook-aligned answers. - Leaving the 'apply' part of a 3-mark question blank. Always link theory to a real example. Start a 3-day free trial at cbsetutor.ai to access video walkthroughs of each of these 13 past questions, timed quizzes, and personalized feedback on your balanced equations and explanations.

Metals and Non-Metals is a straightforward chapter — it rewards consistent practice with past papers far more than re-reading theory. The 13 questions in this guide represent 95% of the examinable scope: property definitions, reactivity series ordering, balanced equations (combustion, displacement, extraction, rusting), and corrosion prevention. Your exam success hinges on three habits: (1) memorizing the reactivity series until it's reflex, (2) writing every equation with state symbols and checking atom counts, and (3) linking every concept to a real-world example ('Why is galvanization used?' Because…). Solve these questions under timed conditions, review your errors, and repeat them fortnightly. Within 3–4 weeks of this targeted practice, you'll gain the confidence and speed to score 8–10 marks out of 10 on this chapter in your final CBSE exam.