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Class 10 Science Chapter 3 Metals and Non-Metals — Formulas & Key Points

Chapter 3 Metals and Non-Metals in NCERT Class 10 Science carries 5-8 marks in the CBSE board exam and forms the foundation for electrochemistry and extraction metallurgy. This formula sheet organises every chemical equation, reactivity trend, extraction process and key definition into tables for rapid revision. Whether you are solving numerical problems on displacement reactions or memorising the reactivity series the night before your exam, this page gives you the complete toolkit.

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Key takeaways

✓The reactivity series determines which metal displaces which: K > Na > Ca > Mg > Al > Zn > Fe > Pb > H > Cu > Hg > Ag > Au > Pt
✓Metal oxides are basic; non-metal oxides are acidic — this dictates pH behaviour in water
✓Roasting converts sulphide ores to oxides in excess oxygen; calcination does the same for carbonate ores by heating without oxygen
✓Ionic compounds form when metals (lose electrons) react with non-metals (gain electrons), resulting in high melting points and conductivity in molten state
✓Corrosion of iron requires both oxygen and moisture: 4Fe + 3O₂ + xH₂O → 2Fe₂O₃·xH₂O (rust)
✓Amphoteric oxides like Al₂O₃ and ZnO react with both acids and bases, making them unique among metal oxides

Reactivity Series of Metals — The Master Table

The reactivity series ranks metals by their ability to lose electrons and form positive ions. A metal higher in the series displaces any metal below it from its salt solution. This series is tested every year in the CBSE Class 10 board paper through displacement reactions, extraction methods, and predicting reaction feasibility. Metals above hydrogen displace H₂ from dilute acids; those below hydrogen do not react with dilute acids at all. The series also determines extraction methods: highly reactive metals (K to Al) require electrolysis, moderately reactive metals (Zn to Fe) can be reduced by carbon or CO, and low-reactivity metals (Cu onwards) occur free in nature or are easily reduced.

Potassium (K) — most reactive, stored in kerosene, extracted by electrolysis
Sodium (Na) — reacts violently with water, extracted by electrolysis of molten NaCl
Calcium (Ca), Magnesium (Mg), Aluminium (Al) — moderately reactive, extracted by electrolysis
Zinc (Zn), Iron (Fe), Lead (Pb) — extracted by reduction with carbon (smelting)
Hydrogen (H) — reference point; metals above it displace H₂ from acids
Copper (Cu), Mercury (Hg), Silver (Ag), Gold (Au), Platinum (Pt) — least reactive, found free or easily reduced

All Key Chemical Equations — Reactions of Metals

This table lists every major reaction type for metals covered in NCERT Class 10 Science Chapter 3. The CBSE board frequently asks you to write balanced equations and predict products. Pay attention to reaction conditions (heat, dilute vs concentrated acid, presence of water or steam). Metals react with oxygen to form oxides (basic in nature), with water or steam to form hydroxides or oxides plus hydrogen, and with acids to form salts and hydrogen gas (only for metals above H in the series). Non-metals form acidic oxides and do not displace hydrogen from acids.

Extraction of Metals — Roasting, Calcination & Reduction Formulas

Extraction metallurgy is the set of processes used to obtain pure metals from their ores. The CBSE syllabus focuses on three key operations: roasting (heating sulphide ores in excess air to convert to oxides), calcination (heating carbonate or hydrated ores in limited air to remove CO₂ or water), and reduction (using carbon, carbon monoxide, or electrolysis to convert oxides to free metals). The choice of method depends on the metal's position in the reactivity series. Highly reactive metals require electrolytic reduction; moderately reactive metals use carbon reduction; least reactive metals are reduced by heat alone or occur free.

Roasting: 2ZnS + 3O₂ → 2ZnO + 2SO₂ (zinc blende to zinc oxide, exothermic, done in a reverberatory furnace)
Calcination: ZnCO₃ → ZnO + CO₂↑ or CaCO₃ → CaO + CO₂↑ (heating in absence of air, used for carbonate and hydrated ores)
Reduction with Carbon: ZnO + C → Zn + CO (used for Zn, Fe, Sn, Pb — metals of medium reactivity)
Reduction with CO: Fe₂O₃ + 3CO → 2Fe + 3CO₂ (blast furnace for iron extraction)
Thermit Reaction: Fe₂O₃ + 2Al → Al₂O₃ + 2Fe + Heat (Al reduces iron oxide, used to weld railway tracks, highly exothermic)
Electrolytic Reduction: 2Al₂O₃(molten) → 4Al + 3O₂ (used for Na, Mg, Ca, Al — cryolite lowers melting point in Hall-Heroult process)

Corrosion Equations and Prevention

Corrosion is the slow conversion of metals into their oxides, carbonates or other compounds by reaction with atmospheric oxygen, moisture, acids or gases. Rusting of iron is the most common example and costs the Indian economy thousands of crores annually. The CBSE Class 10 Science syllabus requires you to know the chemical equation for rust formation, factors affecting corrosion (presence of water, oxygen, electrolytes, pH), and prevention methods (painting, oiling, galvanising, electroplating, alloying). Rusting is an electrochemical process involving oxidation of iron and reduction of oxygen in presence of water.

Rust formation: 4Fe + 3O₂ + xH₂O → 2Fe₂O₃·xH₂O (hydrated ferric oxide, reddish-brown)
Anodic reaction (oxidation): Fe → Fe²⁺ + 2e⁻ at anode regions on iron surface
Cathodic reaction (reduction): O₂ + 4H⁺ + 4e⁻ → 2H₂O at cathode regions
Silver tarnish: 2Ag + H₂S(air) → Ag₂S + H₂ (black silver sulphide coating)
Copper corrosion: 2Cu + O₂ + CO₂ + H₂O → Cu(OH)₂·CuCO₃ (green basic copper carbonate, patina on statues)
Prevention: Galvanising (Zn coating), tinning (Sn coating), painting, oiling, alloying (stainless steel = Fe + Cr + Ni), sacrificial anode (more reactive metal corrodes first)

Ionic Compounds — Formation & Properties

Ionic compounds form when a metal transfers one or more electrons to a non-metal, resulting in oppositely charged ions held together by strong electrostatic forces. Chapter 3 requires you to understand electron transfer during bond formation, write electron-dot structures, and predict properties (high melting/boiling points, solubility in water, electrical conductivity in molten/aqueous state but not in solid state). The CBSE board often asks: 'Why do ionic compounds conduct electricity when molten but not when solid?' The answer lies in ion mobility. Formation of NaCl, MgO, and CaO are standard NCERT examples you must know.

Formation: Metal loses electrons (forms cation), non-metal gains electrons (forms anion). Example: Na → Na⁺ + e⁻; Cl + e⁻ → Cl⁻; Na⁺Cl⁻ forms NaCl
General formula: M → M^n+ + ne⁻ (metal); X + ne⁻ → X^n- (non-metal)
High melting/boiling points due to strong ionic bonds (NaCl melts at 801°C)
Soluble in water (polar solvent) but insoluble in organic solvents like kerosene, petrol
Conduct electricity in molten or aqueous state (ions free to move), not in solid state (ions fixed in lattice)
Hard and brittle — layers shift under stress, like charges repel, crystal shatters

Physical Properties — Metals vs Non-Metals Comparison Table

The CBSE Class 10 Science board exam regularly includes a 3-mark question asking you to list differences between metals and non-metals. The NCERT textbook categorises properties into physical (lustre, malleability, ductility, conductivity, density, melting point, sonority) and chemical (oxide nature, reaction with acids, electropositive vs electronegative character). Most metals are solids at room temperature (exception: mercury), have high density (exception: sodium, potassium), and produce a ringing sound when struck (sonority). Non-metals are poor conductors (exception: graphite, an allotrope of carbon), brittle when solid, and do not possess metallic lustre (exception: iodine).

Chemical Properties — Key Definitions and Tests

Chemical properties describe how metals and non-metals react with oxygen, water, acids, and salts. Metals form basic oxides (react with acids to form salts), are electropositive (lose electrons), and have 1-3 valence electrons. Non-metals form acidic oxides (react with bases), are electronegative (gain electrons), and have 4-8 valence electrons. Amphoteric oxides (Al₂O₃, ZnO, PbO, SnO) react with both acids and bases. The CBSE board tests these through 'identify the gas' questions (H₂ burns with a pop sound; CO₂ turns limewater milky; SO₂ has pungent smell), oxide classification, and predicting products of reactions.

Basic Oxide: Metal oxide that reacts with acids to form salt + water. Example: MgO + 2HCl → MgCl₂ + H₂O. Turns red litmus blue when dissolved in water.
Acidic Oxide: Non-metal oxide that reacts with bases to form salt + water. Example: CO₂ + 2NaOH → Na₂CO₃ + H₂O. Turns blue litmus red.
Amphoteric Oxide: Oxide that reacts with both acids and bases. Examples: Al₂O₃, ZnO. Al₂O₃ + 6HCl → 2AlCl₃ + 3H₂O and Al₂O₃ + 2NaOH → 2NaAlO₂ + H₂O.
Neutral Oxides: CO, NO, N₂O — neither acidic nor basic, do not react with acids or bases.
Test for Hydrogen: Brings a burning splinter near the mouth of test tube — burns with a pop sound.
Test for Carbon Dioxide: Pass through limewater Ca(OH)₂ — turns milky due to CaCO₃ formation: Ca(OH)₂ + CO₂ → CaCO₃↓ + H₂O.

Memory Tricks, Mnemonics and Common Mistakes

Students preparing for the CBSE Class 10 board exams often confuse roasting with calcination, forget the reactivity series order, or write incorrect formulae for ionic compounds. This section consolidates memory tricks that have helped thousands of students score full marks in Chapter 3. Mnemonics work because they convert abstract sequences into memorable phrases. Use these tricks during last-minute revision and write them on the first page of your answer sheet as soon as the exam starts (you can use rough paper for this). Common mistakes include using concentrated HCl instead of dilute, forgetting to show the upward arrow for gases, and mixing up anodic and cathodic reactions in corrosion.

Reactivity Series Mnemonic: 'Please Send Charlie's Monkeys And Zebras In Lead Hammocks, Clothed Heavily In Silver, Gold, Platinum' (K, Na, Ca, Mg, Al, Zn, Fe, Pb, H, Cu, Hg, Ag, Au, Pt)
Roasting vs Calcination: Roasting = Sulphide ore + O₂ (remember 'S' for Sulphide and 'O' for Oxygen are both present). Calcination = Carbonate ore, no O₂ (remember 'C' for Carbonate, 'C' for CO₂ released).
Amphoteric Oxides: 'AlZinc-LeadTin' (Al₂O₃, ZnO, PbO, SnO) — all are amphoteric, react with both acids and bases.
Common Mistake: Writing Na + H₂O → NaOH + H (missing subscript 2). Correct: 2Na + 2H₂O → 2NaOH + H₂↑. Always balance equations.
Common Mistake: Saying 'metals conduct electricity in solid state only.' Correct: metals conduct in both solid and molten states because electrons are free. Ionic compounds conduct only in molten/aqueous state.
Anodic vs Cathodic: Anodic = Anode = Above = Oxidation (remember AAO). Cathodic = Cathode = Reduction (Red Cat).

Worked Examples — Applying the Formulas

This section presents three carefully chosen numerical and conceptual problems that cover displacement reactions, extraction metallurgy, and ionic compound formation. The CBSE Class 10 board paper typically carries 2-3 questions from this chapter worth 6-8 marks in total: one 1-mark MCQ on reactivity series, one 2-mark short answer on extraction or corrosion, and one 3-mark question on writing balanced equations or explaining amphoteric behaviour. Practice these examples, then attempt NCERT in-text and end-of-chapter questions. For personalised doubt-solving with step-by-step photo upload and 24×7 AI tutoring, students across India are now using CBSETUTOR.ai at a flat ₹999/month for all subjects in classes 6-12, with a 3-day free trial.

Last-Minute Revision — One-Glance Summary Box

This is your one-page cheat sheet for the night before the exam or the 15-minute reading time in the exam hall. Revise this box, close your eyes, and recall each point. If you can reproduce the reactivity series, write any five extraction equations, and explain amphoteric behaviour in under 10 minutes, you are board-exam ready for Chapter 3. Print this section or screenshot it on your phone for offline access. Pair it with NCERT exemplar problems and previous years' CBSE question papers (2019-2024) for complete preparation.

Reactivity Series (top 5): K > Na > Ca > Mg > Al | (middle 3): Zn > Fe > Pb > H | (bottom 5): Cu > Hg > Ag > Au > Pt
Metal + O₂ → Metal Oxide (basic). Non-metal + O₂ → Non-metal Oxide (acidic).
Displacement: More reactive metal displaces less reactive metal from its salt solution.
Roasting: Sulphide ore + O₂ → Oxide + SO₂. Calcination: Carbonate ore → Oxide + CO₂ (no O₂).
Reduction: ZnO + C → Zn + CO (for Zn, Fe). 2Al₂O₃ → 4Al + 3O₂ (electrolysis for Na, Mg, Al).
Corrosion (rust): 4Fe + 3O₂ + xH₂O → 2Fe₂O₃·xH₂O. Prevention: galvanising, painting, alloying.
Ionic Compound: High m.p./b.p., conduct in molten state, soluble in water, hard and brittle.
Amphoteric Oxides: Al₂O₃, ZnO react with both HCl and NaOH.
Tests: H₂ (pop sound), CO₂ (limewater milky), O₂ (rekindles glowing splint).
Common Errors: Balance equations, write ↑ for gases, use dilute acids unless stated, do not say ionic compounds conduct in solid state.

How CBSETUTOR.ai Helps with Metals and Non-Metals

Chapter 3 involves memorising reaction sequences, applying the reactivity series to predict outcomes, and writing balanced chemical equations under exam pressure. Many students in Delhi NCR, Mumbai, Bengaluru and Tier-2 cities struggle because coaching classes rush through the chapter in two sessions, leaving no time for doubt-clearing. CBSETUTOR.ai gives every CBSE student a personal AI tutor available 24×7. Upload a photo of any question — whether it is balancing the thermit reaction, explaining why gold does not corrode, or predicting the product of Al + CuO →? — and receive a step-by-step solution in seconds. The platform covers all subjects for classes 6-12 at one flat price of ₹999 per month, with a 3-day free trial. No per-question charges, no hidden fees. Thousands of students used it during the 2024 boards to clarify NCERT in-text questions, practice previous years' papers, and simulate timed chapter tests. For Metals and Non-Metals, the AI tutor provides reaction mechanism breakdowns, mnemonic suggestions, and common error alerts tailored to CBSE marking schemes.

Photo-upload doubt solving for any reaction equation or extraction process question
Step-by-step walkthroughs of NCERT in-text and end-exercises (Chapter 3 has 18 questions)
Reactivity series flashcards and timed quizzes to test recall speed
Corrosion and extraction video explanations aligned with CBSE syllabus
Previous years' board questions (2015-2024) with model answers and examiner tips
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Frequently asked questions

What is the reactivity series and why is it important for CBSE Class 10 board exams?+

The reactivity series ranks metals by their ability to lose electrons: K > Na > Ca > Mg > Al > Zn > Fe > Pb > H > Cu > Hg > Ag > Au > Pt. It predicts displacement reactions, extraction methods, and reaction with acids. CBSE boards test it every year through 1-2 mark MCQs and 3-mark theory questions.

What is the difference between roasting and calcination in metal extraction?+

Roasting heats sulphide ores in excess oxygen to convert them into oxides, releasing SO₂ (2ZnS + 3O₂ → 2ZnO + 2SO₂). Calcination heats carbonate or hydrated ores in limited or no air to remove CO₂ or water (ZnCO₃ → ZnO + CO₂). Both produce metal oxides, but roasting needs oxygen; calcination does not.

Why does iron rust but gold does not? Explain in terms of reactivity.+

Iron is moderately reactive and reacts with atmospheric oxygen and moisture to form hydrated ferric oxide (rust): 4Fe + 3O₂ + xH₂O → 2Fe₂O₃·xH₂O. Gold is the least reactive metal, does not react with oxygen or moisture even over centuries, so it remains shiny and does not corrode. Position in reactivity series determines corrosion tendency.

What are amphoteric oxides? Give two examples with equations.+

Amphoteric oxides react with both acids and bases to form salts and water. Examples: Al₂O₃ and ZnO. With acid: Al₂O₃ + 6HCl → 2AlCl₃ + 3H₂O. With base: Al₂O₃ + 2NaOH → 2NaAlO₂ + H₂O. This dual behaviour is tested frequently in 2-3 mark CBSE questions.

Why do ionic compounds conduct electricity in molten state but not in solid state?+

In solid state, ions are held in fixed positions in a crystal lattice and cannot move, so no conduction. In molten or aqueous state, ions become free to move and carry electric charge, allowing the compound to conduct electricity. This property is unique to ionic compounds and is tested in 2-mark board questions.

How is sodium extracted from sodium chloride? Why is electrolysis used?+

Sodium is extracted by electrolysis of molten NaCl: 2NaCl(l) → 2Na(l) + Cl₂(g). Electrolysis is used because sodium is highly reactive (above carbon in the reactivity series) and cannot be reduced by carbon or CO. Electrolytic reduction is the only method for K, Na, Ca, Mg, and Al.

What is the chemical equation for rusting of iron and how can it be prevented?+

Rusting: 4Fe + 3O₂ + xH₂O → 2Fe₂O₃·xH₂O (hydrated ferric oxide, reddish-brown). Prevention methods include painting (blocks O₂ and H₂O), oiling, galvanising (Zn coating acts as sacrificial anode), electroplating (Cr, Ni), and alloying (stainless steel = Fe + Cr + Ni resists corrosion).

Why is cryolite added during the extraction of aluminium?+

Aluminium is extracted by electrolysis of molten Al₂O₃. Pure Al₂O₃ melts at 2050°C, which is very high and uneconomical. Adding cryolite (Na₃AlF₆) lowers the melting point to ~900°C and increases electrical conductivity, making the Hall-Heroult process cost-effective. This is a standard 2-mark CBSE question.

What is the thermit reaction and where is it used?+

Thermit reaction: Fe₂O₃ + 2Al → Al₂O₃ + 2Fe + Heat. Aluminium (more reactive) reduces iron oxide, releasing so much heat that molten iron is produced. It is used to weld railway tracks and repair broken machine parts. The reaction is highly exothermic and demonstrates the reactivity series in action.

How do I score full marks in the 'write balanced equations' questions in Chapter 3?+

Always write the correct formulae first (check valency), then balance the equation by adjusting coefficients (never change subscripts). Show the state symbols (s, l, g, aq) if asked. Use upward arrow ↑ for gases, downward arrow ↓ for precipitates. Write 'heat' or 'Δ' above the arrow if the reaction needs heating. Practice NCERT in-text and exemplar questions daily.

Related resources

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