Bihar Board Class 10 · Science · Matric exam 2027
Chapter 3: Metals and Non-metals — notes
The chapter’s 8 parts in the book’s order — the first idea of each and the points Medha Ma’am writes on the board — and the summary at the end. The full lesson and a check question for each part are in the app.
1. Physical Properties of Metals and Non-metals
Okay, so let's look at how metals and non-metals look and behave.
- • Metallic lustre: shining surface of pure metals
- • Malleability: beaten into sheets (gold, silver most malleable)
- • Ductility: drawn into wires (gold most ductile)
- • 1 gram gold -> 2 km wire
- • Exceptions: mercury (liquid), Na/K (soft), iodine (lustrous non-metal)
- • Graphite: a non-metal that conducts electricity
2. Chemical Properties: Reaction with Oxygen
Okay, so let's see what happens when metals meet oxygen.
- • Metal + Oxygen -> Metal oxide
- • 2Cu + O2 -> 2CuO (copper(II) oxide, black)
- • 4Al + 3O2 -> 2Al2O3
- • Amphoteric oxides: Al2O3, ZnO (react with acids AND bases)
- • Al2O3 + 6HCl -> 2AlCl3 + 3H2O
- • Na, K kept in kerosene oil (too reactive)
3. Chemical Properties: Reaction with Water and Acids
Okay, so let's see what happens when metals meet water and acids.
- • Metal + Water -> Metal oxide + Hydrogen
- • 2Na + 2H2O -> 2NaOH + H2 + heat (violent)
- • Ca + 2H2O -> Ca(OH)2 + H2 (calcium floats)
- • Mg: reacts only with hot water
- • Al, Fe, Zn: react only with steam
- • Metal + Dilute acid -> Salt + Hydrogen; order: Mg>Al>Zn>Fe
4. Displacement Reactions and the Reactivity Series
Okay, so here's a clever way to compare how reactive metals are.
- • Metal A + Salt solution of B -> Salt solution of A + Metal B
- • (if A displaces B, A is more reactive)
- • Reactivity series (most to least reactive):
- • K, Na, Ca, Mg, Al, Zn, Fe, Pb, H, Cu, Hg, Ag, Au
5. Formation of Ionic Compounds
Now let's understand why metals and non-metals react the way they do.
- • Na -> Na+ + e- (2,8,1 -> 2,8)
- • Cl + e- -> Cl- (2,8,7 -> 2,8,8)
- • Na+ + Cl- -> NaCl (ionic/electrovalent compound)
- • Mg -> Mg2+ + 2e- ; forms MgCl2
- • Ionic compounds: formed by transfer of electrons
6. Properties of Ionic Compounds
Okay, so ionic compounds have strong forces holding the oppositely charged ions together.
- • Ionic compounds: solid, hard, brittle
- • High melting/boiling points (NaCl: 1074 K)
- • Soluble in water, insoluble in kerosene/petrol
- • Solid state: do NOT conduct electricity
- • Molten/dissolved state: DO conduct electricity (ions free to move)
7. Occurrence and Extraction of Metals
Okay, so, metals are found in the earth's crust as minerals.
- • Mineral: naturally occurring element/compound
- • Ore: mineral with high % of metal, profitably extracted
- • Low reactivity metals: found free (Au, Ag, Cu)
- • Roasting: heating sulphide ore in excess air
- • Calcination: heating carbonate ore in limited air
- • ZnO + C -> Zn + CO ; High reactivity metals: electrolytic reduction
8. Corrosion, Alloys and the Thermit Reaction
Okay, so let's talk about what happens to metals over time, and how we protect them.
- • Silver -> silver sulphide (black); Copper -> copper carbonate (green)
- • Iron + moist air -> rust (brown, flaky)
- • Prevention: painting, oiling, greasing, galvanising, alloying
- • Galvanising: coating iron/steel with zinc
- • Alloy: homogeneous mixture of metals (or metal + non-metal)
- • Fe2O3 + 2Al -> 2Fe + Al2O3 + Heat (thermit reaction)
Summary
You learned that metals are lustrous, malleable, ductile, sonorous and good conductors, while non-metals generally lack these properties, though there are exceptions like mercury, iodine and graphite. Metals react with oxygen to form mostly basic oxides, some of which, like Al2O3 and ZnO, are amphoteric, and they react with water and acids at different rates, giving us the reactivity series from potassium down to gold. Using displacement reactions, you saw how a more reactive metal pushes out a less reactive one from its salt solution. Then you learned how metals form ionic compounds by transferring electrons to non-metals, and how these ionic compounds are hard, high-melting, water-soluble and conduct electricity only when molten or dissolved. Finally, you learned how metals occur as minerals and ores, how they are extracted depending on their place in the reactivity series through roasting, calcination, reduction and electrolysis, and how corrosion is fought through galvanising, alloying and other methods, with the thermit reaction even being used to join railway tracks.
AskMedha · Medha Ma’am — Bihar Board Class 10 Science, Chapter 3. Written from the textbook, checked twice.
Questions parents and students ask
- How do I get the "Metals and Non-metals" notes as a PDF?
- Press "Save as PDF" — the phone’s print sheet opens; choose "Save as PDF" there. The PDF holds the notes only.
- Where are these notes written from?
- From the chapter’s own textbook text, part by part, in the book’s own terms; a second, independent model then checked every part against the book. The full lesson, a check question for each part and the practice are in the AskMedha app.
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