1
What is the shining surface of a pure metal called?
💡 Hint:
The shine that returns after rubbing with sandpaper.
Explanation:
The shining surface of a pure metal is called metallic lustre.
Class 10 · Science · Chapter 3 · बिहार बोर्ड (BSEB)CBSE · NCERT 2026-27
Metals and Non-metals
Metals and Non-metals
How to use this page:
1. Read — activities 3.1 to 3.14, diagram, worked example, board tip
2. Check — each lesson has its own questions; the number follows the lesson
3. Mastery ★ — all of that lesson correct. Redo the wrong ones
4. Lesson 8 has the reactivity series and lesson 12 has the three test tubes.
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- 1 Metallic lustre and hardness — Activities 3.1 and 3.2
- 2 Malleability and ductility — Activities 3.3 and 3.4
- 3 Heat, electricity and sound — Activities 3.5 to 3.7
- 4 The oxide formed on burning — Activity 3.8
- 5 Metals burn in air — Activity 3.9
- 6 Metals and water — Activity 3.10
- 7 Metals and dilute acids — Activity 3.11
- 8 Displacement and the reactivity series — Activity 3.12
- 9 How metals and non-metals join — a transfer of electrons
- 10 Properties of ionic compounds — Activity 3.13
- 11 From ore to metal — three paths by reactivity
- 12 Refining and corrosion — Activity 3.14
- Chapter winner — every lesson at mastery ★
🎬 Shorts
This chapter has no Short on the channel yet, so ten empty cards are not shown. The notes, diagrams and checks are complete.
📄 PDF download — notes + answer key
Metallic lustre and hardness — Activities 3.1 and 3.2
धातु की चमक और कठोरता — क्रियाकलाप 3.1, 3.2 · NCERT 3.1.1 · Activities 3.1, 3.2
Tell metals and non-metals apart by how they lookNotes
Iron, copper, aluminium, magnesium, sodium, lead and zinc are metals. Carbon, sulphur, iodine, oxygen and hydrogen are non-metals. Bromine is the non-metal that is a liquid at room temperature.
A clean metal surface shines. That shine is called metallic lustre.
Activity 3.1 — clean the surface with sandpaperActivity
Take samples of iron, copper, aluminium and magnesium. Note the colour and the surface. Then rub each with sandpaper. After rubbing, every sample starts to shine. A thin coat of dust and oxide had been hiding the lustre.
Activity 3.2 — try a knife; sodium is the exceptionActivity
Iron, copper, aluminium and magnesium do not cut easily with a knife — they are hard. Hold sodium with tongs, dry it between the folds of filter paper and cut it on a watch-glass. It cuts like butter.
Caution: do not hold sodium in a bare hand. It reacts quickly with moisture in the air, so it is stored in kerosene.
Worked exampleExample
Question: Why is sodium kept in kerosene?
Answer: Sodium is very reactive. In open air it reacts with both oxygen and moisture. Kerosene keeps it away from air and water.
10-second revision
- The shine of a pure metal is metallic lustre; sandpaper brings it back
- Most metals are hard; sodium and potassium can be cut with a knife
- Sodium is stored in kerosene
Board tip · BSEBBoard tip
In an objective item, sodium is stored in kerosene, not in water.
Board tip · CBSEBoard tip
CBSE asks the reason — reaction with moisture and oxygen in air. Do not stop at “it is reactive”.
Check your understandingall correct = mastery ★
2
Sodium can be cut easily with a knife.
Explanation:
True — the alkali metals are soft. Iron and copper do not cut with a knife.
3
Sodium metal is kept under which liquid?
💡 Hint:
It reacts quickly with air and moisture.
Explanation:
Kerosene keeps sodium out of contact with air and water.
4
In Activity 3.1, what changes after the metal is rubbed with sandpaper?
Model answer (board format)
The dull coat of dirt or oxide comes off and the surface shines again. That is metallic lustre.
Check your answer:
Malleability and ductility — Activities 3.3 and 3.4
आघातवर्ध्यता और तन्यता — क्रियाकलाप 3.3, 3.4 · NCERT 3.1.1 · Activities 3.3, 3.4
Activity 3.3 — sheets with a hammerActivity
Take pieces of iron, zinc, lead and copper. Place one on an iron block and strike it four or five times with a hammer. The metal becomes a flat sheet instead of crumbling. The property of being beaten into thin sheets is malleability. Gold and silver are the most malleable.
Activity 3.4 — drawing a wireActivity
Copper, aluminium, iron and lead are available as wires. The property of being drawn into a thin wire is ductility. Gold is the most ductile — about 2 kilometres of wire can be drawn from one gram of gold.
Because of these two properties a metal can be shaped into a vessel, a wire or jewellery. Non-metals break when struck — they are brittle.
Keep the two words apart
Malleable = sheet. Ductile = wire. Papers often swap the two words.
10-second revision
- Malleability = thin sheets under a hammer
- Ductility = a thin wire; gold is the most ductile, about 2 km from 1 g
- Non-metals are brittle
Board tip · BSEBBoard tip
A BSEB definition is two lines — write the name of the property and one example (gold).
Board tip · CBSEBoard tip
CBSE asks why vessels are made of metal — give both malleability and conduction of heat.
Check your understandingall correct = mastery ★
1
Beating a metal into a thin sheet is called what?
💡 Hint:
A sheet is made with a hammer, not by drawing a wire.
Explanation:
Beating into a sheet is malleability. Drawing a wire is ductility.
2
About 2 kilometres of wire can be drawn from one gram of gold.
Explanation:
True — gold is the most ductile metal.
3
Non-metals break when struck, so they are called ______.
💡 Hint:
The English word is brittle.
Explanation:
Non-metals are brittle. Metals are malleable.
4
Which metal is the most ductile?
💡 Hint:
The same metal gives kilometres of wire from one gram.
Explanation:
Gold is the most ductile. Gold and silver are also the most malleable.
Heat, electricity and sound — Activities 3.5 to 3.7
ऊष्मा, विद्युत और ध्वनि — क्रियाकलाप 3.5 से 3.7 · NCERT 3.1.1–3.1.2 · Activities 3.5, 3.6, 3.7 · Table 3.1
Activity 3.5 — a pin in wax, and heatActivity
Clamp an aluminium or copper wire on a stand. Fix a pin to the free end with wax. Heat the wire near the clamp with a spirit lamp. After a while the wax melts and the pin falls, but the wire itself does not melt. A metal is a good conductor of heat and has a high melting point. Silver and copper are the best conductors of heat. Lead and mercury are poorer.
Activities 3.6 and 3.7 — the bulb, then the non-metalsActivity
Place the metal between terminals A and B of a circuit. The bulb glows — the metal conducts electricity. House wires have a coat of PVC or rubber so that the current stays inside. A metal rings when struck — it is sonorous. That is why a school bell is metal.
Repeat the same checks on carbon (coal or graphite), sulphur and iodine. Non-metals are usually insulators and brittle.
The exceptions in Table 3.1 — these earn the marksCaution
- Every metal except mercury is solid at room temperature. Mercury is a liquid.
- Gallium and caesium melt if you keep them on your palm.
- Iodine is a non-metal, yet it is lustrous.
- Allotropes of carbon: diamond is the hardest natural substance. Graphite conducts electricity even though it is a non-metal.
- Lithium, sodium and potassium are soft, with low density and low melting points.
So physical properties alone cannot finish the classification. Chemical properties draw the clear line.
10-second revision
- Metals conduct heat and electricity and are sonorous
- Mercury is a liquid metal; Ga and Cs melt on the palm
- Iodine is a lustrous non-metal; graphite conducts; diamond is the hardest
Board tip · BSEBBoard tip
An exceptions MCQ comes almost every year. Learn mercury, graphite, iodine and gallium as one list.
Board tip · CBSEBoard tip
Reason items: “Why is the bell metal?” — sonorous. “Why rubber on a wire?” — the metal conducts, the coat does not.
Check your understandingall correct = mastery ★
1
Which metal is a liquid at room temperature?
💡 Hint:
Bromine is a non-metal.
Explanation:
Mercury is a liquid metal at room temperature. Bromine is a liquid non-metal.
2
Graphite is a non-metal, yet it conducts electricity.
Explanation:
True — graphite is an allotrope of carbon and conducts electricity. Diamond does not.
3
Why is a school bell made of metal?
💡 Hint:
A sound is produced on striking.
Explanation:
Metals are sonorous, so a bell is made of metal.
4
The two metals that melt on the palm are gallium and ______.
💡 Hint:
The melting point is very low.
Explanation:
Gallium and caesium melt from the warmth of the palm.
5
Write one exception about conduction in metals and non-metals.
Model answer (board format)
Graphite is a non-metal, yet it conducts electricity. Or: lead and mercury are comparatively poor conductors of heat.
Check your answer:
The oxide formed on burning — Activity 3.8
जलने पर ऑक्साइड — क्रियाकलाप 3.8 · NCERT opening of 3.2 · Activity 3.8
Activity 3.8 — magnesium and sulphurActivity
Burn a magnesium ribbon. Collect the ash, dissolve it in water and test it with red and blue litmus. The ash is magnesium oxide. The solution turns red litmus blue — a metal oxide is basic.
2Mg + O2 → 2MgO
Now burn sulphur powder. Hold a test tube over it to collect the fumes, add a little water and shake. This solution turns blue litmus red — a non-metal oxide is acidic.
S + O2 → SO2
The rule in one sentenceNotes
Metal + oxygen → a basic oxide. Non-metal + oxygen → an acidic oxide. The next lesson has two exceptions — the oxides of aluminium and zinc behave both ways.
Worked exampleExample
Question: What will aqueous MgO do to red litmus, and aqueous SO₂ to blue litmus?
Answer: MgO is basic, so red litmus turns blue. SO₂ forms an acid in water, so blue litmus turns red.
10-second revision
- Burning Mg gives MgO — basic, red litmus turns blue
- Burning S gives SO₂ — acidic, blue litmus turns red
- Metal oxide basic, non-metal oxide acidic — amphoteric comes later
Board tip · BSEBBoard tip
The equation and the litmus colour are asked in one answer. Write both.
Board tip · CBSEBoard tip
“Why basic?” — a metal oxide behaves like a base in water.
Check your understandingall correct = mastery ★
1
What does the aqueous ash of a magnesium ribbon do to litmus?
💡 Hint:
MgO is a basic oxide.
Explanation:
A base turns red litmus blue. MgO is basic.
2
The oxide formed by burning sulphur is acidic.
Explanation:
True — SO₂ gives an acid in water and blue litmus turns red.
3
Balance the equation by filling in the coefficients (blank = 1).
Mg + O2 → MgO
💡 Hint:
Oxygen has two atoms on the left and one in MgO on the right.
Explanation: 2Mg + O2 → 2MgO — magnesium oxide.
4
Write one difference between the oxide of a metal and of a non-metal, with an example.
Model answer (board format)
A metal oxide is basic, for example MgO turns red litmus blue. A non-metal oxide is acidic, for example SO₂ turns blue litmus red.
Check your answer:
Metals burn in air — Activity 3.9
धातुएँ वायु में जलती हैं — क्रियाकलाप 3.9 · NCERT 3.2.1 · Activity 3.9 · amphoteric oxides
Activity 3.9 — which metal burns readilyActivity
With the teacher, try burning magnesium, aluminium, zinc, iron and copper. Magnesium burns with a dazzling white flame. Aluminium and zinc also form oxides. Iron is slower. Copper only forms a black coat of copper oxide on the surface. Metals do not all burn in oxygen at the same rate — that is the first hint of reactivity.
2Cu + O2 → 2CuO4Al + 3O2 → 2Al2O3Amphoteric oxides and the protective coatNotes
Aluminium oxide and zinc oxide react with both acids and bases. They are amphoteric.
Al2O3 + 6HCl → 2AlCl3 + 3H2OAl2O3 + 2NaOH → 2NaAlO2 + H2OSodium and potassium are so reactive that they can catch fire in open air, so they stay in kerosene. A thin oxide coat on magnesium, aluminium and zinc stops more oxygen getting in — the metal underneath is protected.
Worked exampleExample
Question: Why is Al₂O₃ called amphoteric? Write an equation with one acid and one base.
Answer: Because it forms a salt with both an acid and a base. With HCl it gives AlCl₃, and with NaOH it gives NaAlO₂.
10-second revision
- The reactivity order shows on burning too: Mg easy, Cu only on the surface
- Al₂O₃ and ZnO are amphoteric
- Na and K in kerosene; a protective coat on Mg, Al and Zn
Board tip · BSEBBoard tip
The definition of amphoteric is one line: reacts with both acid and base. Examples Al₂O₃, ZnO.
Board tip · CBSEBoard tip
The kerosene reason joins lesson 1 — here add that the metal can burn in oxygen.
Check your understandingall correct = mastery ★
1
Which oxide is amphoteric?
💡 Hint:
It forms a salt with both an acid and a base.
Explanation:
Al₂O₃ and ZnO are amphoteric. MgO is only basic, SO₂ is acidic.
2
Sodium and potassium are kept in ______.
💡 Hint:
They can catch fire in air.
Explanation:
Kerosene keeps them away from oxygen and moisture.
3
Copper burns with a dazzling flame like magnesium.
Explanation:
False — copper only forms black CuO on the surface. Magnesium burns with a dazzling white flame.
4
Balance the equation by filling in the coefficients (blank = 1).
Al + O2 → Al2O3
💡 Hint:
Al₂O₃ has 3 oxygen atoms. The left side has O₂.
Explanation: 4Al + 3O2 → 2Al2O3
5
An aluminium article left in the air does not spoil all the way through. Why?
Model answer (board format)
A thin layer of Al₂O₃ forms on the surface. The layer stops more oxygen from reaching the metal.
Check your answer:
Metals and water — Activity 3.10
धातु और जल — क्रियाकलाप 3.10 · NCERT 3.2.2 · Activity 3.10
Activity 3.10 — cold water, hot water, steamActivity
With the teacher, take the same metals. Start with cold water.
- Potassium and sodium react with cold water so fast that the hydrogen catches fire.
- Calcium also reacts with cold water, but less violently.
- Magnesium hardly reacts with cold water; with hot water it gives hydrogen.
- Aluminium, zinc and iron do not react with cold or hot water, only with steam.
- Lead, copper, silver and gold do not react with water.
Equations worth keepingNotes
2Na + 2H2O → 2NaOH + H2Ca + 2H2O → Ca(OH)2 + H22Al + 3H2O → Al2O3 + 3H23Fe + 4H2O → Fe3O4 + 4H2
The aluminium and iron equations are for steam. The oxide of iron here is Fe₃O₄, not FeO.
Worked exampleExample
Question: Why does a flame appear as soon as sodium is put in cold water, and not with copper?
Answer: Sodium is very reactive. The reaction is exothermic and the H₂ that forms catches fire. Copper is below hydrogen in the reactivity series, so it does not release H₂ from water.
10-second revision
- K and Na catch fire in cold water; Ca is less violent; Mg needs hot water
- Al, Zn and Fe only with steam; iron gives Fe₃O₄
- Pb, Cu, Ag and Au do not react with water
Board tip · BSEBBoard tip
If the order is asked, write K > Na > Ca > Mg > Al > Zn > Fe, then Pb, Cu, Ag, Au do not react.
Board tip · CBSEBoard tip
The difference between steam and cold water is often missed. For iron write both “steam” and Fe₃O₄.
Check your understandingall correct = mastery ★
1
Which metal reacts with cold water so fast that the hydrogen catches fire?
💡 Hint:
This one has to be kept in kerosene.
Explanation:
Sodium and potassium react rapidly with cold water and the H₂ catches fire.
2
Which oxide does iron give when it reacts with water?
💡 Hint:
Iron does not react with cold water.
Explanation:
3Fe + 4H₂O (steam) → Fe₃O₄ + 4H₂.
3
Copper releases hydrogen from both cold water and steam.
Explanation:
False — copper, silver and gold do not react with water.
4
Balance the equation by filling in the coefficients (blank = 1).
Na + H2O → NaOH + H2
💡 Hint:
H₂ has two hydrogen atoms.
Explanation: 2Na + 2H2O → 2NaOH + H2
5
Why does magnesium behave differently in cold water and in hot water?
Model answer (board format)
The reaction with cold water is very slow. In hot water the rate rises and hydrogen gas is formed. Mg is less reactive than Na.
Check your answer:
Metals and dilute acids — Activity 3.11
धातु और तनु अम्ल — क्रियाकलाप 3.11 · NCERT 3.2.3 · Activity 3.11 · aqua regia
Activity 3.11 — dilute HCl and the pop testActivity
Take a metal sample and dilute hydrochloric acid in a test tube. A reactive metal fizzes. The gas burns with a pop near a burning splint — it is hydrogen.
Zn + 2HCl → ZnCl2 + H2
The order of speed is roughly Mg > Al > Zn > Fe. Copper does not release hydrogen from dilute HCl. Only metals above hydrogen release H₂ from a dilute acid.
Nitric acid and aqua regia — two exceptionsCaution
Dilute nitric acid is a strong oxidising agent. It does react with a metal, but it usually does not give hydrogen gas — it oxidises H₂ to water. Magnesium and manganese are the exceptions; they do give H₂ with dilute HNO₃.
Gold and platinum do not dissolve in a single acid. Aqua regia — a 3 : 1 mixture of concentrated HCl and concentrated HNO₃ — dissolves them.
Worked exampleExample
Question: Copper does not dissolve in dilute HCl, but aqua regia dissolves gold. Give one reason for each.
Answer: Copper is below hydrogen in the reactivity series, so it does not displace H₂ from dilute HCl. Aqua regia produces nascent chlorine, which turns gold into a soluble chloride.
10-second revision
- Metal + dilute HCl → salt + H₂, if the metal is above H
- Order Mg > Al > Zn > Fe; not Cu
- HNO₃ usually gives no H₂; aqua regia = 3 HCl : 1 HNO₃
Board tip · BSEBBoard tip
The pop test joins Chapter 2 — write both the name of the gas and the test.
Board tip · CBSEBoard tip
The aqua regia ratio is 3:1. Reversing it is a common mistake.
Check your understandingall correct = mastery ★
1
How is the gas from zinc and dilute HCl identified?
💡 Hint:
The gas is hydrogen.
Explanation:
H₂ gives a pop near a burning splint.
2
Copper releases hydrogen from dilute hydrochloric acid.
Explanation:
False — copper is less reactive than hydrogen.
3
In aqua regia the ratio of concentrated HCl to concentrated HNO₃ is ______.
💡 Hint:
There is more HCl.
Explanation:
Aqua regia is a 3:1 mixture of concentrated HCl and concentrated HNO₃. It dissolves gold and platinum.
4
Why does magnesium give hydrogen even with dilute nitric acid?
Model answer (board format)
Usually HNO₃ oxidises hydrogen to water. Magnesium and manganese are exceptions — they do give H₂ with dilute HNO₃.
Check your answer:
5
Which is the correct order of releasing hydrogen from a dilute acid?
💡 Hint:
The most reactive metal is the fastest.
Explanation:
Mg > Al > Zn > Fe. Copper is not in this list.
Displacement and the reactivity series — Activity 3.12
विस्थापन और सक्रियता श्रेणी — क्रियाकलाप 3.12 · NCERT 3.2.4–3.2.5 · Activity 3.12 · Table 3.2
Activity 3.12 — pull a metal out of its salt solutionActivity
Put an iron nail into blue copper sulphate solution. The blue colour fades and a red-brown coat of copper forms on the nail. Iron is more reactive than copper, so it displaces copper.
Fe + CuSO4 → FeSO4 + Cu
The reverse pair does nothing. A copper strip in zinc sulphate shows no change — copper cannot push zinc out. The rule: a more reactive metal displaces a less reactive metal from its salt solution.
The series in one breath
K, Na, Ca, Mg, Al, Zn, Fe, Pb, H, Cu, Hg, Ag, Au
Hydrogen is not a metal. It is placed in the series to show who can release H₂ from a dilute acid. A metal above H can.
10-second revision
- Fe + CuSO₄ → FeSO₄ + Cu; blue fades, red copper appears
- A more reactive metal displaces a less reactive one from its salt
- Series: K Na Ca Mg Al Zn Fe Pb H Cu Hg Ag Au
Board tip · BSEBBoard tip
Reversing the series is the most common mistake. K is at the top, Au at the bottom.
Board tip · CBSEBoard tip
A colour-change case is common: blue CuSO₄ + Fe → pale green FeSO₄.
Check your understandingall correct = mastery ★
1
What happens when an iron nail is placed in CuSO₄ solution?
💡 Hint:
Iron is more reactive than copper.
Explanation:
Fe displaces Cu from CuSO₄. The solution becomes pale green FeSO₄.
2
Balance the equation by filling in the coefficients (blank = 1).
Fe + CuSO4 → FeSO4 + Cu
💡 Hint:
Each side already has one of each atom.
Explanation: Fe + CuSO4 → FeSO4 + Cu
3
Copper displaces zinc from zinc sulphate solution.
Explanation:
False — zinc is more reactive than copper. A less reactive metal does not displace a more reactive one.
4
Why is hydrogen given a place in the reactivity series?
Model answer (board format)
Metals placed above hydrogen can release H₂ from a dilute acid. Those below, such as Cu and Ag, cannot.
Check your answer:
5
Which metal is the least reactive in the series?
💡 Hint:
At the far right, or the bottom, of the series.
Explanation:
The series starts at K and ends at Au. Gold is the least reactive.
How metals and non-metals join — a transfer of electrons
धातु और अधातु कैसे जुड़ते हैं — इलेक्ट्रॉन का लेन-देन · NCERT 3.3 · Table 3.3 · ionic bond
The octet and the ionsNotes
A configuration is stable when the outer shell has 8 electrons (2 for hydrogen). A metal has few outer electrons, so it gives them away and becomes a cation. A non-metal has more outer electrons, so it takes them and becomes an anion.
Sodium (2, 8, 1) loses one electron to become Na⁺ (2, 8). Chlorine (2, 8, 7) gains one electron to become Cl⁻ (2, 8, 8). Opposite charges attract and make an ionic bond — the compound NaCl.
Two chlorines in magnesium chlorideNotes
Magnesium (2, 8, 2) loses two electrons and becomes Mg²⁺. Each chlorine takes one electron. So one Mg²⁺ needs two Cl⁻ — the formula is MgCl₂.
In the same way oxygen needs two electrons in sodium oxide, so two Na⁺ are required — Na₂O.
Worked exampleExample
Question: In NaCl, who gives the electron and who takes it? Write the symbols of the ions.
Answer: Sodium gives one electron and becomes Na⁺. Chlorine takes that electron and becomes Cl⁻.
10-second revision
- A metal gives electrons and becomes a cation; a non-metal takes them and becomes an anion
- Na (2,8,1) → Na⁺ ; Cl (2,8,7) → Cl⁻ ; the compound is NaCl
- MgCl₂ has one Mg²⁺ and two Cl⁻
Board tip · BSEBBoard tip
In an electron-dot structure show only the outer shell. One dot on Na and seven on Cl.
Board tip · CBSEBoard tip
If the formula is asked, balance the charge: Mg²⁺ needs two Cl⁻.
Check your understandingall correct = mastery ★
1
When sodium chloride forms, what does sodium become?
💡 Hint:
A metal gives electrons away.
Explanation:
Sodium loses one electron and becomes Na⁺. Chlorine becomes Cl⁻.
2
An ionic bond is formed by sharing electrons.
Explanation:
False — an ionic bond is formed by transfer of electrons. Sharing happens in a covalent bond.
3
The formula of magnesium chloride is ______.
💡 Hint:
Mg loses two electrons.
Explanation:
Mg²⁺ and two Cl⁻ make MgCl₂.
4
Write the formation of NaCl in three short steps.
Model answer (board format)
1. Na (2, 8, 1) loses one electron and becomes Na⁺ (2, 8). 2. Cl (2, 8, 7) gains that electron and becomes Cl⁻ (2, 8, 8). 3. Electrostatic attraction between Na⁺ and Cl⁻ forms NaCl.
Check your answer:
Properties of ionic compounds — Activity 3.13
आयनिक यौगिकों के गुण — क्रियाकलाप 3.13 · NCERT 3.3.1 · Activity 3.13 · Table 3.4
Activity 3.13 — melting point and the bulbActivity
Take ionic compounds such as sodium chloride and potassium iodide.
- They are hard and brittle. The attraction between opposite ions is strong, so a hammer makes a layer slip and like charges face each other and break the piece.
- Melting and boiling points are high. The melting point of NaCl is about 1074 K. Separating the ions takes a lot of energy.
- In the solid state the bulb does not glow — the ions are locked and cannot move.
- When melted, or dissolved in water, the bulb glows — the ions move freely and carry the current.
Worked exampleExample
Question: Why is solid NaCl not a conductor of electricity, while its aqueous solution is?
Answer: In the solid, Na⁺ and Cl⁻ are fixed in place. In water they can move separately, so a current flows.
10-second revision
- Ionic compounds are hard, brittle and have high melting points
- They do not conduct electricity as solids
- In the molten or aqueous state the ions move and the bulb glows
Board tip · BSEBBoard tip
Write the three states: solid — no; molten — yes; aqueous — yes.
Board tip · CBSEBoard tip
Give the reason as “whether the ions can move”, not “water conducts”.
Check your understandingall correct = mastery ★
1
Why does the bulb not glow in solid sodium chloride?
💡 Hint:
The same compound conducts when it is melted.
Explanation:
In the solid the ions are fixed. On melting or dissolving they move and carry the current.
2
Ionic compounds generally have high melting points.
Explanation:
True — breaking the attraction between opposite ions takes a lot of energy. NaCl melts at about 1074 K.
3
An ionic compound becomes a ______ of electricity when it dissolves in water.
💡 Hint:
The ions become free.
Explanation:
In aqueous solution the ions move, so the compound becomes a conductor.
4
Why is an ionic compound brittle?
Model answer (board format)
A hammer-blow makes one layer of ions slip. Ions of the same charge then face each other, and repulsion breaks the crystal.
Check your answer:
From ore to metal — three paths by reactivity
अयस्क से धातु — सक्रियता के तीन रास्ते · NCERT 3.4.1–3.4.5 · calcination, roasting, thermite
Mineral, ore and gangueNotes
In the earth’s crust metals are usually found as compounds. Such a natural substance is a mineral. A mineral from which the metal can be extracted profitably is an ore. The sandy or earthy impurity with the ore is gangue. Separating the ore from gangue is enrichment.
Metals of low reactivity (Cu, Ag, Au) are sometimes found free. Those in the middle (Zn, Fe, Pb) occur as oxides, sulphides or carbonates. The most reactive (K, Na, Ca, Mg, Al) are obtained by electrolysis of the molten salt.
The three pathsNotes
Low reactivity: heat the sulphide in air to the oxide, then heat further to the metal. Heating mercury oxide alone is enough.
2HgO → 2Hg + O2Middle: heating a sulphide ore in plenty of air is roasting. Heating a carbonate in limited air is calcination. The oxide is reduced with carbon.
2ZnS + 3O2 → 2ZnO + 2SO2ZnCO3 → ZnO + CO2ZnO + C → Zn + COThermite: aluminium pulls iron out of iron oxide. The same heat is used to join railway tracks.
Fe2O3 + 2Al → 2Fe + Al2O3Most reactive: carbon cannot extract them. Electrolysis of molten NaCl, or of alumina with cryolite, is used.
10-second revision
- Ore = a profitable mineral; gangue = the sandy impurity
- Roasting is for a sulphide, plenty of air; calcination is for a carbonate, limited air
- Thermite: Fe₂O₃ + 2Al → 2Fe + Al₂O₃
Board tip · BSEBBoard tip
In the definitions of roasting and calcination the words “plenty of air” and “limited air” are required.
Board tip · CBSEBoard tip
In thermite the reducing agent is aluminium, not carbon. Joining a rail is the use.
Check your understandingall correct = mastery ★
1
Heating a sulphide ore in plenty of air is called what?
💡 Hint:
The process for a carbonate has the other name.
Explanation:
Roasting is heating a sulphide ore in plenty of air. Calcination is heating a carbonate in limited air.
2
Gold and silver are sometimes found in the free state.
Explanation:
True — they are low in the reactivity series, so they do not hide inside compounds.
3
Balance the equation by filling in the coefficients (blank = 1).
Fe2O3 + Al → Fe + Al2O3
💡 Hint:
Al₂O₃ has two aluminium atoms.
Explanation: Fe2O3 + 2Al → 2Fe + Al2O3 — the thermite reaction.
4
The earthy or sandy impurity in an ore is called ______.
💡 Hint:
The English word is gangue.
Explanation:
Gangue is the unwanted sand or earth mixed with the ore.
5
Write the two steps, with equations, from zinc sulphide to zinc.
Model answer (board format)
Roasting: 2ZnS + 3O₂ → 2ZnO + 2SO₂. Then reduction with carbon: ZnO + C → Zn + CO.
Check your answer:
Refining and corrosion — Activity 3.14
शुद्धिकरण और संक्षारण — क्रियाकलाप 3.14 · NCERT 3.4.6, 3.5, 3.5.1 · Activity 3.14
Electrolytic refining of copperNotes
Impure copper is the anode and a thin strip of pure copper is the cathode. The electrolyte is acidified copper sulphate. Cu²⁺ leaves the anode into the solution and pure copper deposits on the cathode. Insoluble impurities settle below the anode as anode mud — it sometimes contains silver and gold.
Activity 3.14 — rust needs bothActivity
Put clean iron nails in three test tubes.
- A: enough water to cover the nail, with air as well. After a few days, red-brown rust.
- B: boiled distilled water with a layer of oil so that air cannot dissolve. No rust.
- C: dry air with anhydrous calcium chloride. No moisture, no rust.
Rust needs both air (oxygen) and water together. The formula of rust is hydrated iron(III) oxide — Fe₂O₃·xH₂O.
Ways to stop corrosionNotes
- Paint, oil or grease — keep air and water off the surface.
- Galvanisation — a coat of zinc on iron. Zinc corrodes first and protects the iron.
- Electroplating — a thin coat of a metal such as chromium.
- Alloys: brass = copper + zinc, bronze = copper + tin, solder = lead + tin. Stainless steel = iron + carbon + nickel + chromium.
10-second revision
- Refining copper: impure anode, pure cathode, CuSO₄ solution
- Rust needs both O₂ and H₂O; formula Fe₂O₃·xH₂O
- Galvanisation = a coat of Zn; stainless steel contains Cr and Ni
Board tip · BSEBBoard tip
Swapping anode and cathode is a common mistake. The impurity is at the anode; pure metal deposits on the cathode.
Board tip · CBSEBoard tip
Practise by drawing the three tubes yourself. Write in one sentence each what the oil layer and CaCl₂ do.
Check your understandingall correct = mastery ★
1
In the electrolytic refining of copper, where does pure copper deposit?
💡 Hint:
The impure metal is the anode.
Explanation:
Pure copper deposits on the cathode. Insoluble impurity becomes anode mud.
2
Iron rusts in dry air alone.
Explanation:
False — rust needs both oxygen and water. Tube C of Activity 3.14 stays dry and does not rust.
3
How does galvanisation protect iron from rust?
Model answer (board format)
A layer of zinc is coated on the iron. Zinc, being more reactive, corrodes first and keeps air and water off the iron. Even if the coat is scratched, the zinc nearby keeps protecting the iron.
Check your answer:
4
Which metals are mainly mixed with iron in stainless steel?
💡 Hint:
Bronze is copper and tin.
Explanation:
Stainless steel contains iron, carbon, nickel and chromium.
5
Balance the equation by filling in the coefficients (blank = 1).
HgO → Hg + O2
💡 Hint:
O₂ has two oxygen atoms.
Explanation: 2HgO → 2Hg + O2 — heating the oxide is enough for a metal of low reactivity.
❓ Full question bank — with answers and explanations — 72 questions
Pick a type. The 55 lesson checks are separate — each lesson has as many as its topic needs. All correct earns mastery ★.
BSEB modelpractice · not annual60 tried · 0 correctMultiple choiceMCQ170 tried · 0 correctTrue / falseTrue / false80 tried · 0 correctFill in the blanksFill80 tried · 0 correctMatchMatch20 tried · 0 correctAssertion–reasonAssertion–reason40 tried · 0 correctBalancingBalancing60 tried · 0 correctIdentifyIdentify30 tried · 0 correctShort and longVSA, SA, LA120 tried · 0 correctCBSE-stylenot a PYQ60 tried · 0 correct
No question is marked as a verified past paper. The BSEB set is a model for practice. CBSE items are CBSE-style, not a copy of any year’s paper.
Multiple choice
0/17Pick one option. A wrong try brings a hint.
1
What is metallic lustre?
💡 Hint:
The shine that returns after sandpaper.
Explanation:
The shining surface of a pure metal is called metallic lustre.
2
Which metal is the most ductile?
💡 Hint:
About two kilometres of wire from one gram.
Explanation:
Gold is the most ductile.
3
The metal that is liquid at room temperature is —
💡 Hint:
Bromine is a non-metal.
Explanation:
Mercury is a liquid metal. Bromine is a liquid non-metal.
4
Which non-metal conducts electricity?
💡 Hint:
An allotrope of carbon.
Explanation:
Graphite conducts electricity even though it is a non-metal. Diamond does not.
5
What is aqueous MgO like?
💡 Hint:
The oxide of a metal.
Explanation:
MgO is basic and turns red litmus blue.
6
An amphoteric oxide is —
💡 Hint:
Reacts with both acid and base.
Explanation:
ZnO and Al₂O₃ are amphoteric.
7
A metal that catches fire in cold water is —
💡 Hint:
At the top of the series.
Explanation:
Potassium and sodium react rapidly with cold water.
8
Which oxide does iron give with steam?
💡 Hint:
The equation is 3Fe + 4H₂O.
Explanation:
With steam, iron gives Fe₃O₄.
9
In aqua regia, HCl : HNO₃ is —
💡 Hint:
More HCl.
Explanation:
Aqua regia is a 3:1 mixture of concentrated HCl and concentrated HNO₃.
10
What colour does the solution become when an iron nail is placed in CuSO₄?
💡 Hint:
The colour of FeSO₄.
Explanation:
Blue CuSO₄ changes to pale green FeSO₄ and copper deposits on the nail.
11
Hydrogen in the reactivity series sits between which pair?
💡 Hint:
Table 3.2.
Explanation:
The order is Pb, H, Cu.
12
In NaCl the sodium ion is —
💡 Hint:
A metal gives an electron.
Explanation:
Sodium loses one electron and becomes Na⁺.
13
Solid NaCl does not conduct electricity because —
💡 Hint:
It conducts when melted.
Explanation:
In the solid the ions are fixed.
14
Heating a carbonate ore in limited air is called —
💡 Hint:
The process for a sulphide has the other name.
Explanation:
Calcination is for a carbonate. Roasting is for a sulphide, in plenty of air.
15
The reducing agent in the thermite reaction is —
💡 Hint:
The metal used to join railway tracks.
Explanation:
In Fe₂O₃ + 2Al → 2Fe + Al₂O₃, aluminium is the reducing agent.
16
In refining copper, the pure metal deposits —
💡 Hint:
The impure rod is the anode.
Explanation:
Pure copper deposits on the cathode.
17
What is needed for rusting?
💡 Hint:
The three tubes of Activity 3.14.
Explanation:
Rust does not form unless both moisture and air are present.
True or false
0/81
Sodium is kept immersed in water.
Explanation:
False — sodium is kept in kerosene. With water it catches fire.
2
Iodine is lustrous even though it is a non-metal.
Explanation:
True — this is an exception to classifying by physical properties.
3
All metals release hydrogen from dilute HCl.
Explanation:
False — only metals above hydrogen. Copper does not.
4
A more reactive metal displaces a less reactive metal from its salt solution.
Explanation:
True — this is the rule of Activity 3.12.
5
Ionic compounds are good conductors of electricity in the solid state.
Explanation:
False — ions cannot move in the solid. Conduction happens in the molten or aqueous state.
6
In roasting the ore is heated in a limited supply of air.
Explanation:
False — roasting uses plenty of air. Limited air belongs to calcination.
7
In galvanisation a layer of zinc is coated on iron.
Explanation:
True — zinc corrodes first and protects the iron.
8
Stainless steel is an element, not an alloy.
Explanation:
False — it contains iron, carbon, nickel and chromium.
Fill in the blanks
0/81
Drawing a metal into a wire is called ______.
💡 Hint:
Wire = ductility.
Explanation:
Making a sheet is malleability.
2
The metals that melt on the palm are gallium and ______.
💡 Hint:
Gallium and caesium.
Explanation:
Very low melting point.
3
Aqua regia dissolves gold and ______.
💡 Hint:
Aqua regia dissolves gold and platinum.
Explanation:
Two metals of very low reactivity.
4
The most reactive metal in the series is ______.
💡 Hint:
Potassium is the most reactive and gold the least.
Explanation:
The first name in the series.
5
The formula of magnesium chloride is ______.
💡 Hint:
Mg²⁺ and two Cl⁻ make MgCl₂.
Explanation:
Mg loses two electrons.
6
The sandy impurity of an ore is called ______.
💡 Hint:
Gangue is unwanted sand or earth.
Explanation:
The English word is gangue.
7
The general formula of rust is Fe₂O₃·______H₂O.
💡 Hint:
Rust is hydrated iron(III) oxide, Fe₂O₃·xH₂O.
Explanation:
The number of water molecules is not fixed.
8
Brass is an alloy of copper and ______.
💡 Hint:
Brass = copper + zinc. Bronze = copper + tin.
Explanation:
Bronze contains tin.
Match
0/21
Match the property with its meaning.
Column B: A. A thin sheet · B. A thin wire · C. A sound on striking · D. A shining surface
1. Malleability
2. Ductility
3. Sonority
4. Metallic lustre
Explanation:
Sheet, wire, sound, shine — in that order.
2
Match the alloy with its components.
Column B: A. Cu + Zn · B. Cu + Sn · C. Pb + Sn · D. Fe + C + Ni + Cr
1. Brass
2. Bronze
3. Solder
4. Stainless steel
Explanation:
Brass has zinc, bronze has tin, solder has lead and tin, stainless steel has nickel and chromium.
Assertion–reason
0/4Check both statements, then see whether the reason explains the assertion.
1
Assertion (A): Sodium is kept in kerosene.
Reason (R): Sodium reacts rapidly with moisture and oxygen in the air.
Explanation:
Both are true and R correctly explains A.
2
Assertion (A): Graphite conducts electricity.
Reason (R): Graphite is a metal.
Explanation:
A is true. R is false — graphite is an allotrope of carbon, a non-metal.
3
Assertion (A): An iron nail turns red-brown in blue copper sulphate.
Reason (R): Iron is more reactive than copper and displaces it.
Explanation:
Both are true and R is the correct reason.
4
Assertion (A): Solid sodium chloride does not conduct electricity.
Reason (R): Solid NaCl contains no ions at all.
Explanation:
A is true. R is false — the ions are present, but they cannot move in the solid.
Balance the equation
0/61
Balance the equation by filling in the coefficients (blank = 1).
Mg + O2 → MgO
Explanation: 2Mg + O2 → 2MgO
2
Balance the equation by filling in the coefficients (blank = 1).
Cu + O2 → CuO
Explanation: 2Cu + O2 → 2CuO
3
Balance the equation by filling in the coefficients (blank = 1).
Al + O2 → Al2O3
Explanation: 4Al + 3O2 → 2Al2O3
4
Balance the equation by filling in the coefficients (blank = 1).
Zn + HCl → ZnCl2 + H2
Explanation: Zn + 2HCl → ZnCl2 + H2
5
Balance the equation by filling in the coefficients (blank = 1).
Fe2O3 + Al → Fe + Al2O3
Explanation: Fe2O3 + 2Al → 2Fe + Al2O3
6
Balance the equation by filling in the coefficients (blank = 1).
ZnO + C → Zn + CO
Explanation: ZnO + C → Zn + CO
Classify
0/31
Place each substance as metal, non-metal or alloy.
Mercury
Graphite
Brass
Iodine
Explanation:
Mercury is a metal, graphite and iodine are non-metals, brass is an alloy.
2
Place each oxide as basic, acidic or amphoteric.
MgO
SO₂
Al₂O₃
ZnO
Explanation:
MgO is basic, SO₂ is acidic, Al₂O₃ and ZnO are amphoteric.
3
How does the metal react with water?
Sodium
Iron
Copper
Explanation:
Sodium with cold water, iron only with steam, copper not with water.
Very short answer
0/51
Define malleability in one line.
Model answer (board format)
Malleability is the property of a metal of being beaten into thin sheets.
Check your answer:
2
What does sonorous mean?
Model answer (board format)
A metal that produces a sound when struck on a hard surface is called sonorous.
Check your answer:
3
What is aqua regia?
Model answer (board format)
A 3:1 mixture of concentrated hydrochloric acid and concentrated nitric acid. It dissolves gold and platinum.
Check your answer:
4
Write one difference between an ore and a mineral.
Model answer (board format)
A mineral is a natural compound of a metal in the earth. An ore is a mineral from which the metal can be extracted profitably. Every ore is a mineral; every mineral is not an ore.
Check your answer:
5
What is anode mud?
Model answer (board format)
In electrolytic refining the insoluble impurities of the anode settle at the bottom. That deposit is called anode mud.
Check your answer:
Short answer
0/41
Write three physical differences between metals and non-metals.
Model answer (board format)
Metals are lustrous, malleable and conduct electricity. Non-metals are usually dull, brittle and insulators. Exceptions: graphite conducts, iodine is lustrous.
Check your answer:
2
Write the reactivity series and say why copper does not release hydrogen from dilute HCl.
Model answer (board format)
K, Na, Ca, Mg, Al, Zn, Fe, Pb, H, Cu, Hg, Ag, Au. Copper is below hydrogen, so it does not displace H₂ from a dilute acid.
Check your answer:
3
Write the difference between roasting and calcination, with one equation each.
Model answer (board format)
Roasting is heating a sulphide in plenty of air: 2ZnS + 3O₂ → 2ZnO + 2SO₂. Calcination is heating a carbonate in limited air: ZnCO₃ → ZnO + CO₂.
Check your answer:
4
Write three ways to prevent rusting.
Model answer (board format)
A coat of paint or oil, galvanisation (a coat of zinc), and making an alloy such as stainless steel.
Check your answer:
Long answer
0/31
Show by an activity that both air and water are necessary for rusting.
Model answer (board format)
Put iron nails in three tubes. A has both water and air — it rusts. B has boiled water with a layer of oil so air cannot dissolve — no rust. C has dry air with anhydrous CaCl₂ — no rust. So both oxygen and moisture are needed.
Check your answer:
2
Explain the formation of NaCl from Na by transfer of electrons. Also write two properties of an ionic compound.
Model answer (board format)
Na (2, 8, 1) loses one electron and becomes Na⁺. Cl (2, 8, 7) gains it and becomes Cl⁻. Opposite charges form NaCl. Properties: a high melting point, and it does not conduct electricity as a solid.
Check your answer:
3
Write the three classes of metal extraction based on reactivity. Give one example of each.
Model answer (board format)
Oxides of metals of low reactivity are only heated, for example Hg from HgO. Oxides of metals in the middle are reduced with carbon, for example ZnO + C → Zn + CO. The most reactive metals come from electrolysis of the molten salt, for example Na from NaCl.
Check your answer:
BSEB model paper · practice
0/6This model set is for practice. It is not a question from any year’s annual examination. Annual questions will be added only when a source page is available.
1
Which of the following is brittle?
💡 Hint:
A non-metal breaks when struck.
Explanation:
Sulphur is a non-metal and is brittle.
2
The metal coated on iron in galvanisation is —
💡 Hint:
The reactive metal that protects from rust.
Explanation:
Galvanisation uses a layer of zinc.
3
Bronze is an alloy of copper and ______.
💡 Hint:
Bronze = copper + tin.
Explanation:
Brass contains zinc.
4
Why does the surface of aluminium stay protected even in open air?
Model answer (board format)
A thin layer of aluminium oxide forms on the surface and stops more oxygen from getting in.
Check your answer:
5
Balance the equation by filling in the coefficients (blank = 1).
Na + H2O → NaOH + H2
Explanation: 2Na + 2H2O → 2NaOH + H2
6
What is the reactivity series of metals? Write two uses of it — one with an acid, one with displacement.
Model answer (board format)
It is the list of metals in decreasing reactivity: K, Na, Ca, Mg, Al, Zn, Fe, Pb, H, Cu, Hg, Ag, Au. A metal above hydrogen releases H₂ from a dilute acid. A more reactive metal displaces a less reactive metal from its salt solution, for example Fe pulls Cu out of CuSO₄.
Check your answer:
CBSE-style questions
0/6These are competency-based practice questions. They are not copies of a CBSE paper.
1
Four metals are given: Al, Cu, Fe, Zn. The correct order of the speed of hydrogen from dilute HCl is —
💡 Hint:
Copper is below hydrogen.
Explanation:
Al > Zn > Fe, and Cu does not give H₂ with dilute HCl.
2
A student kept three nails. A in open water, B in boiled water covered with oil, C with dry CaCl₂. Which one rusts?
💡 Hint:
Both air and water are needed.
Explanation:
Only A has both air and water.
3
Assertion (A): The thermite reaction is used to join railway tracks.
Reason (R): Aluminium reduces iron oxide and a lot of heat is released.
Explanation:
Both are true and R is the correct reason.
4
Assertion (A): Magnesium gives hydrogen with dilute nitric acid.
Reason (R): Nitric acid is never an oxidising agent.
Explanation:
A is true. R is false — HNO₃ is a strong oxidising agent. Mg and Mn are the exceptions.
5
A grey powder is added to a blue solution. The colour becomes pale green and a red-brown solid settles. Identify the powder and the solution, and write the equation.
Model answer (board format)
The powder is iron and the solution is copper sulphate. Fe + CuSO₄ → FeSO₄ + Cu.
Check your answer:
6
A white salt does not light a bulb as a solid, but the bulb glows when it is dissolved in water. Is the salt ionic or covalent? Write two more properties of this class.
Model answer (board format)
The salt is ionic, because on dissolving the ions move and carry the current. This class has high melting points and the compounds are brittle.
Check your answer:
🏛️ Board exam corner — Bihar Board (BSEB)— CBSE
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🧠 What you learned + equation sheet
What you learned
- A metal is lustrous, malleable, ductile, a conductor of heat and electricity, and sonorous. Exceptions: mercury is liquid, graphite conducts, iodine is a lustrous non-metal.
- A metal oxide is basic (MgO). A non-metal oxide is acidic (SO₂). Al₂O₃ and ZnO are amphoteric.
- K and Na catch fire in cold water. Mg reacts with hot water. Al, Zn and Fe react only with steam. Cu, Ag and Au do not react with water.
- The order of H₂ from dilute acid is Mg > Al > Zn > Fe. Cu gives none. Aqua regia, 3:1, dissolves Au and Pt.
- Reactivity series: K, Na, Ca, Mg, Al, Zn, Fe, Pb, H, Cu, Hg, Ag, Au. A more reactive metal displaces a less reactive one from its salt.
- Rust needs both air and water. Prevention: paint, galvanisation and alloys.
| What | Balanced equation |
|---|---|
| Magnesium, air | 2Mg + O₂ → 2MgO |
| Aluminium, air | 4Al + 3O₂ → 2Al₂O₃ |
| Sodium, water | 2Na + 2H₂O → 2NaOH + H₂ |
| Iron, steam | 3Fe + 4H₂O → Fe₃O₄ + 4H₂ |
| Displacement | Fe + CuSO₄ → FeSO₄ + Cu |
| Thermite | Fe₂O₃ + 2Al → 2Fe + Al₂O₃ |
| Roasting | 2ZnS + 3O₂ → 2ZnO + 2SO₂ |
| Calcination | ZnCO₃ → ZnO + CO₂ |
| Carbon reduction | ZnO + C → Zn + CO |
| Low-reactivity oxide | 2HgO → 2Hg + O₂ |
The notes are original writing. The textbook was used only for activity order and numbers. “Verified” will be used only on a question that has a source page.