Metals & Non-Metals
Key Concepts
| # | Concept | Explanation |
|---|---|---|
| 1 | Metallic Lustre | Metals shine when cut/ polished because free electrons reflect light. |
| 2 | Malleability & Ductility | Metals can be beaten into sheets (malleable) & drawn into wires (ductile) due to non-directional metallic bonding. |
| 3 | Conductivity | Metals conduct heat & electricity via delocalised electrons; non-metals are insulators (except graphite). |
| 4 | Ionisation & Valency | Metals lose e⁻ → cations (+), valency = group no.; non-metals gain e⁻ → anions (–), valency = 8 – group no. |
| 5 | Reactivity Series | K > Na > Ca > Mg > Al > Zn > Fe > Pb > H > Cu > Hg > Ag > Au; higher metal displaces lower from salt solution. |
| 6 | Amphoteric Oxides | Al₂O₃, ZnO react with both acid & base → salt + water. |
| 7 | Alloy | Solid solution of metals (or metal + non-metal); e.g. brass (Cu-Zn), stainless steel (Fe-Cr-Ni). |
| 8 | Occurrence | Reactive metals (Na, K) exist as chlorides/carbonates; noble metals (Au, Ag) occur native. |
15 Practice MCQs
1. Which metal is liquid at room temperature?
**A. Ga B. Hg C. Cs D. Fr** **Answer: B** Mercury (Hg) is the only metal liquid at 25 °C. **Trick**: “Hg = High-grade liquid metal.” **Tag**: Physical state2. The oxide of which element turns red litmus blue?
**A. Sulphur B. Carbon C. Magnesium D. Phosphorus** **Answer: C** MgO is basic; basic oxides turn red litmus blue. **Trick**: “Metal-oxide = Basic.” **Tag**: Nature of oxides3. Aluminium is obtained by electrolysis of which ore?
**A. Bauxite B. Haematite C. Magnetite D. Copper pyrites** **Answer: A** Bauxite (Al₂O₃·2H₂O) → Hall-Héroult process. **Trick**: “Alu = Baux-ite.” **Tag**: Extraction4. Which non-metal conducts electricity?
**A. Diamond B. Sulphur C. Graphite D. Phosphorus** **Answer: C** Graphite has delocalised electrons between layers. **Trick**: “G for Graphite & Good conductor.” **Tag**: Conductivity exception5. Iron is galvanised by coating with—
**A. Sn B. Zn C. Cu D. Cr** **Answer: B** Zinc layer protects Fe sacrificially. **Trick**: “Galva-Zn-c.” **Tag**: Corrosion prevention6. The reaction 2Pb + O₂ → 2PbO is an example of—
**A. Reduction B. Oxidation C. Displacement D. Decomposition** **Answer: B** Pb gains oxygen → oxidised. **Trick**: “Oxygen added = Oxidation.” **Tag**: Redox7. Which alloy contains Cu & Ni?
**A. Bronze B. Brass C. Constantan D. Solder** **Answer: C** Constantan (Cu 55 % + Ni 45 %). **Trick**: “Con-stan-tan → Cu-Ni.” **Tag**: Alloys8. Most abundant metal in Earth’s crust is—
**A. Fe B. Al C. Ca D. Na** **Answer: B** Al ≈ 8 % by weight. **Trick**: “Alu-minimum space, maximum share.” **Tag**: Abundance9. Which metal forms amphoteric oxide?
**A. Na B. Cu C. Zn D. Au** **Answer: C** ZnO reacts with both HCl & NaOH. **Trick**: “Zn = Zero preference (acid/base).” **Tag**: Amphoteric10. Thermite mixture contains—
**A. Fe₂O₃ + Al B. CuO + Zn C. Al₂O₃ + Mg D. PbO + C** **Answer: A** Fe₂O₃ + Al → Fe + Al₂O₃ + heat (welding). **Trick**: “Fe-Al = Fire-welding.” **Tag**: Thermite reaction11. Which gas is released when Zn reacts with dil. H₂SO₄?
**A. O₂ B. SO₂ C. H₂ D. CO₂** **Answer: C** Zn + H₂SO₄ → ZnSO₄ + H₂↑ **Trick**: “Metal + Acid → Salt + H₂.” **Tag**: Metal-acid reaction12. Stainless steel contains—
**A. Fe, Cr, Ni B. Fe, C, Mn C. Cu, Zn D. Fe, Cu, Sn** **Answer: A** Cr (≈18 %) + Ni (≈8 %) prevent rusting. **Trick**: “SS = Strong & Shiny → Cr-Ni.” **Tag**: Alloys13. Non-metal used to vulcanise rubber is—
**A. P B. S C. Cl D. I** **Answer: B** Sulphur cross-links rubber chains. **Trick**: “S = Soft-rubber Stiffener.” **Tag**: Non-metal use14. Which metal is stored under kerosene?
**A. Ca B. Mg C. Na D. Al** **Answer: C** Na reacts violently with moisture. **Trick**: “Na = Kero-sene-guard.” **Tag**: Storage15. In the reactivity series, which metal can displace copper from CuSO₄ solution?
**A. Ag B. Au C. Fe D. Hg** **Answer: C** Fe is above Cu → displaces it. **Trick**: “Higher kicks Lower.” **Tag**: DisplacementSpeed Tricks
| Situation | Shortcut | Example |
|---|---|---|
| Basic vs Acidic oxide | “Metal-oxide = Basic, Non-metal-oxide = Acidic” | CO₂ acidic, CaO basic |
| Liquid metals at 30 °C | “Hg Ga Cs” – remember Hg is only pure liquid, Ga & Cs melt in hand | |
| Conductivity exception | “Graphite is the only non-metal conductor” – G & Good | |
| Displacement rule | “Upper metal kicks lower metal out of salt solution” | Zn + CuSO₄ → ZnSO₄ + Cu |
| Alloy composition | “Bronze = Cu-Sn, Brass = Cu-Zn, Stainless = Fe-Cr-Ni” – B-Sn, B-Zn, SS-CrNi |
Quick Revision
| Point | Detail |
|---|---|
| 1 | Metals have 1-3 valence electrons, form cations. |
| 2 | Non-metals have 4-7 valence electrons, form anions. |
| 3 | Al is extracted from bauxite by Hall-Héroult process. |
| 4 | Iron is obtained in blast furnace; limestone removes impurities as slag. |
| 5 | Copper is refined by electrolytic refining; pure Cu deposits at cathode. |
| 6 | Galvanisation = Zn coating; Tin-plating = Sn coating. |
| 7 | Thermite reaction: Fe₂O₃ + Al → Fe + Al₂O₃ (used in rail welding). |
| 8 | Amphoteric oxides: Al₂O₃, ZnO, PbO. |
| 9 | Aqua-regia (3 HCl : 1 HNO₃) dissolves Au & Pt. |
| 10 | Mercury & Al compounds cause water pollution called “heavy-metal pollution”. |
BETA
