Is it correct to say: Writing 'metals are always solid'?

Mercury (Hg) is LIQUID at room temperature. Gallium melts at 30 °C.

Is it correct to say: Confusing roasting with calcination?

ROASTING = heating SULPHIDE ore in EXCESS air (2ZnS + 3O₂ → 2ZnO + 2SO₂). CALCINATION = heating CARBONATE / hydrated ore in LIMITED air (CaCO₃ → CaO + CO₂).

Is it correct to say: Assuming all metal oxides are basic?

Al₂O₃, ZnO, PbO are AMPHOTERIC (react with both acids and bases).

Is it correct to say: Writing Cu + HCl → CuCl₂ + H₂?

Cu is BELOW H in the reactivity series ⇒ NO reaction with dilute HCl. Cu dissolves only in oxidising acids (dil. HNO₃, hot conc. H₂SO₄).

Is it correct to say: Confusing thermite reaction as reduction of Al by Fe?

It is the OPPOSITE — Al reduces Fe₂O₃ (because Al is more reactive). Product: molten Fe.

Is it correct to say: Saying 'ionic compounds have low melting points'?

Ionic compounds have HIGH melting/boiling points due to strong electrostatic forces. They are usually solids at room temperature.

Metals and Non-Metals

Physical and chemical properties, reactivity series, extraction of metals, corrosion — NCERT Class 10 Chemistry Ch 3

📐 9 formulas✏️ 3 examples🎯 6 practice⚖️ 5-6 marks🏫 CBSE📚 Class 10✓ 2025–26 syllabus

💡

Board Exam Tips

→Reactivity series (K > Na > Ca > Mg > Al > Zn > Fe > Pb > (H) > Cu > Hg > Ag > Au) — write it out on rough sheet before the exam starts.
→Ionic compound formation (Na + Cl → Na⁺Cl⁻ with electron dot diagram) — a favourite 3-mark question.
→Extraction: (a) reactive metals — electrolysis; (b) moderately reactive — reduction of oxide with C; (c) least reactive — heating in air. Learn the classification.
→Amphoteric oxides (Al₂O₃, ZnO) — must-know exceptions.
→Difference between roasting and calcination — 2 marks safe.

📐 Formulas(9)

Ionic Bond Formation★ Board fav

N a ⟶ N a^{+} + e^{-}; C l + e^{-} ⟶ C l^{-}

Metal + Oxygen

2 M + O_{2} ⟶ 2 M O

Metal + Water

2 N a + 2 H_{2} O ⟶ 2 N a O H + H_{2} (g)

Metal + Dilute Acid★ Board fav

M + 2 H C l ⟶ M C l_{2} + H_{2} (g)

Displacement in Salt Solution

F e + C u S O_{4} ⟶ F e S O_{4} + C u

Amphoteric Oxide

A l_{2} O_{3} + 6 H C l ⟶ 2 A l C l_{3} + 3 H_{2} O

Reduction of Metal Oxide (Smelting)★ Board fav

Z n O + C ⟶ Z n + C O

Thermite Reaction

F e_{2} O_{3} + 2 A l ⟶ 2 F e + A l_{2} O_{3}

Electrolytic Refining

Impure M (anode) ⟶ M^{n +} (a q) + n e^{-}; M^{n +} + n e^{-} ⟶ M (cathode)

✏️ Solved Examples

1Solved Exampleeasy4 steps

Show the formation of magnesium chloride (MgCl₂) using electron-dot structures.

Electronic configurations

M g (2, 8, 2); C l (2, 8, 7)

2Solved Exampleboard4 steps

The chief ore of zinc is zinc blende (ZnS). Explain how zinc metal is extracted from this ore. Give equations.

Step 1 — Concentration by froth flotation (sulphide ore concentrated using pine oil + water; ore floats).

3Solved ExampleHOTS5 steps

You are given metals A, B and C. A reacts with cold water; B reacts only with steam; C does not react even with steam. Arrange in decreasing order of reactivity and give one example each. Explain your reasoning.

Reactivity with water decreases DOWN the activity series: K/Na/Ca react with cold water; Mg with hot; Al/Zn/Fe with steam; Cu/Ag/Au do not react.

⚠️ Traps & Common Mistakes

⚠️Common Mistakes6

1
Writing 'metals are always solid'
✓Mercury (Hg) is LIQUID at room temperature. Gallium melts at 30 °C.
2
Confusing roasting with calcination
✓ROASTING = heating SULPHIDE ore in EXCESS air (2ZnS + 3O₂ → 2ZnO + 2SO₂). CALCINATION = heating CARBONATE / hydrated ore in LIMITED air (CaCO₃ → CaO + CO₂).
3
Assuming all metal oxides are basic
✓Al₂O₃, ZnO, PbO are AMPHOTERIC (react with both acids and bases).
4
Writing Cu + HCl → CuCl₂ + H₂
✓Cu is BELOW H in the reactivity series ⇒ NO reaction with dilute HCl. Cu dissolves only in oxidising acids (dil. HNO₃, hot conc. H₂SO₄).
5
Confusing thermite reaction as reduction of Al by Fe
✓It is the OPPOSITE — Al reduces Fe₂O₃ (because Al is more reactive). Product: molten Fe.
6
Saying 'ionic compounds have low melting points'
✓Ionic compounds have HIGH melting/boiling points due to strong electrostatic forces. They are usually solids at room temperature.

🎯 Practice Yourself

🎯Practice Yourself6 questions

Q1
State one example each of a metal that is (a) liquid, (b) very soft (can be cut with a knife), (c) the best conductor of electricity.
Q2
Give the balanced equation for the reaction of aluminium with hot concentrated NaOH.
Q3
Why is copper used for making electric wires, and aluminium for high-voltage transmission?
Q4
Name the process used to extract sodium metal from its salt. Write the electrode reaction.
Q5
What is galvanisation? Why is it done?
Q6
Explain why sodium is kept immersed in kerosene.

📝 Notes

Metals and Non-Metals

The Periodic Table divides elements broadly into metals (left/centre) and non-metals (right). This chapter contrasts their physical + chemical behaviour and traces the industrial journey ore → pure metal.

Physical properties — the general trend

| Property | Metals | Non-metals | |---|---|---| | State | Solid (except Hg) | Solid, liquid or gas | | Lustre | Shiny | Dull (except I₂, diamond) | | Malleability / Ductility | High | Brittle | | Conductivity (heat + electricity) | Good | Poor (except graphite) | | Density / m.p. | High | Low (mostly) | | Sonorous | Yes | No |

Reactivity series (must memorise)

K > Na > Ca > Mg > Al > Zn > Fe > Pb > (H) > Cu > Hg > Ag > Au

Mnemonic: "Please Send Charlie's Monkeys And Zebra Into Little (Hot) Cages Housed Some Amazing Aunts."

Extraction — decides the method

Top of series (K, Na, Ca, Mg, Al): highly reactive ⇒ ores stable ⇒ electrolysis of molten salt.
Middle (Zn, Fe, Pb, Cu): ore usually oxide/sulphide/carbonate ⇒ convert to oxide (roasting / calcination) → reduce with C (or Al for thermite).
Bottom (Ag, Au, Hg): occur free or as sulphide ⇒ just heating in air or displacement.

Ionic vs covalent compounds

| Feature | Ionic (metal + non-metal) | Covalent (non-metal + non-metal) | |---|---|---| | Bond | Transfer of electrons | Sharing of electrons | | State | Solid | Solid / liquid / gas | | M.p. / B.p. | High | Low | | Solubility | Water yes, organics no | Organics yes, water usually no | | Conductivity | In molten/aqueous state | Non-conductor |