Chapter 3: Metals and Non-metals | Class 10 Science

Class 10 Science Chapter 3

⚗️ Metals and Non-metals

Easy-to-understand notes with solved questions for school students

Table of Contents

3.1 Physical Properties

🔩 3.1.1 Metals — Physical Properties

Metals have some special physical properties that make them useful in everyday life. Let's explore them one by one!

✨ 1. Lustre (Shiny Surface)

Pure metals have a shining surface called metallic lustre. When you rub a metal piece with sandpaper, it looks shiny and bright.

🔨 2. Malleability (Can be beaten into sheets)

Metals can be beaten into thin, flat sheets without breaking. This property is called malleability.

Imp Gold and silver are the most malleable metals.

🧵 3. Ductility (Can be drawn into wires)

The ability of a metal to be pulled into thin wires is called ductility. Gold is the most ductile metal — 1 gram of gold can be drawn into a 2 km long wire!

🌡️ 4. Good Conductors of Heat

Metals allow heat to pass through them easily. Silver and copper are the best conductors of heat. Lead and mercury are poor conductors.

⚡ 5. Good Conductors of Electricity

Metals allow electric current to pass through them. That is why electrical wires are made of copper or aluminium. The coating on wires (PVC/rubber) is a non-metal and does not conduct electricity.

🔔 6. Sonorous (Makes a ringing sound)

Metals produce a ringing sound when struck. That is why school bells and musical instruments are made of metals.

Imp Exceptions you must remember:

Mercury is the only metal that is liquid at room temperature.
Gallium & Caesium melt in the palm of your hand (very low melting points).
Iodine is a non-metal but it is lustrous (shiny).
Graphite (carbon) is a non-metal that conducts electricity.
Diamond (carbon) is the hardest natural substance known.
Sodium, Potassium, Lithium are so soft they can be cut with a knife.

🌿 3.1.2 Non-metals — Physical Properties

Non-metals are generally the opposite of metals. They can be solids or gases. Bromine is the only liquid non-metal at room temperature. Examples: carbon, sulphur, iodine, oxygen, hydrogen.

Property	Metals	Non-metals
Lustre	Shiny	Dull (except iodine)
Hardness	Generally hard	Generally soft (diamond is exception)
Malleability	Malleable	Brittle (break on hammering)
Ductility	Ductile	Not ductile
Heat Conduction	Good conductors	Poor conductors
Electricity	Good conductors	Poor conductors (graphite exception)
Sonorous	Yes	No
State at room temp	Solid (except Hg)	Solid/Gas (except Br which is liquid)

❓ Questions (Section 3.1)

Q1. Give an example of a metal which:

(i) is a liquid at room temperature

Answer: Mercury (Hg)

(ii) can be easily cut with a knife

Answer: Sodium (Na)

(iii) is the best conductor of heat

Answer: Silver (Ag)

(iv) is a poor conductor of heat

Answer: Lead (Pb)

Q2. Explain the meanings of malleable and ductile.

Malleable: A metal that can be beaten into thin sheets without breaking is called malleable. Example: Gold, Silver.
Ductile: A metal that can be drawn into thin wires without breaking is called ductile. Example: Gold (most ductile).

3.2 Chemical Properties of Metals

🔥 3.2.1 Metals + Oxygen (Burning in Air)

Almost all metals combine with oxygen to form metal oxides. Metal oxides are basic in nature.

Metal + Oxygen → Metal Oxide

For example:

2Cu + O₂ → 2CuO (Copper(II) oxide — black colour)

4Al + 3O₂ → 2Al₂O₃ (Aluminium oxide)

Amphoteric Oxides: Some metal oxides (like Al₂O₃ and ZnO) react with both acids AND bases. These are called amphoteric oxides.

Al₂O₃ + 6HCl → 2AlCl₃ + 3H₂O (reacts with acid)

Al₂O₃ + 2NaOH → 2NaAlO₂ + H₂O (reacts with base)

Oxides of sodium and potassium dissolve in water to form alkalis:

Na₂O(s) + H₂O(l) → 2NaOH(aq)

K₂O(s) + H₂O(l) → 2KOH(aq)

Imp

K, Na — react so vigorously they catch fire; stored in kerosene
Mg, Al, Zn, Pb — surface is covered by a protective oxide layer
Iron (Fe) — iron filings burn vigorously in burner flame
Cu — does not burn; forms black copper(II) oxide layer
Ag, Au — do not react with oxygen even at high temperatures

💡 Did You Know? — Anodising
Anodising is a process where aluminium is made the anode in an electrolytic cell with dilute sulphuric acid. Oxygen released at the anode forms a thick, protective oxide layer on aluminium that is resistant to corrosion and can also be dyed in attractive colours.

💧 3.2.2 Metals + Water

Metal + Water → Metal Oxide + Hydrogen

Metal Oxide + Water → Metal Hydroxide

Metal	Reacts with	Equation
K (Potassium)	Cold water (violently)	2K + 2H₂O → 2KOH + H₂↑ + Heat
Na (Sodium)	Cold water (violently)	2Na + 2H₂O → 2NaOH + H₂↑ + Heat
Ca (Calcium)	Cold water (less violent)	Ca + 2H₂O → Ca(OH)₂ + H₂↑
Mg (Magnesium)	Hot water	Mg + 2H₂O → Mg(OH)₂ + H₂↑
Al, Fe, Zn	Steam only	2Al + 3H₂O → Al₂O₃ + 3H₂↑ 3Fe + 4H₂O → Fe₃O₄ + 4H₂↑
Pb, Cu, Ag, Au	Does NOT react	—

Note: Calcium and Magnesium float on water because hydrogen bubbles stick to their surface.

🧪 3.2.3 Metals + Dilute Acids

Metal + Dilute Acid → Salt + Hydrogen Gas

Reactivity order with dilute HCl: Mg > Al > Zn > Fe. Copper does not react with dilute HCl at all.

Imp Metals + Nitric Acid (HNO₃): Hydrogen gas is NOT produced. HNO₃ is a strong oxidising agent — it oxidises H₂ to water. Exception: Mg and Mn react with very dilute HNO₃ to give H₂.

💡 Aqua Regia
Aqua Regia = Concentrated HCl : Concentrated HNO₃ in ratio 3:1. It can dissolve even gold and platinum — metals that cannot be dissolved by either acid alone. The name means "Royal Water" in Latin.

⚗️ 3.2.4 Metals + Solutions of other Metal Salts

A more reactive metal displaces a less reactive metal from its salt solution. This is called a displacement reaction.

Metal A + Salt of Metal B → Salt of A + Metal B

Example: Iron is more reactive than copper, so:

Fe(s) + CuSO₄(aq) → FeSO₄(aq) + Cu(s)

The blue colour of copper sulphate solution fades and a reddish-brown copper deposit forms on the iron nail.

3.2.5 The Reactivity Series

Metals are arranged from most reactive to least reactive in the Activity Series.

Imp Metals above hydrogen in the activity series can displace hydrogen from dilute acids. Metals below hydrogen (Cu, Hg, Ag, Au) cannot.

❓ Questions (Section 3.2)

Q1. Why is sodium kept immersed in kerosene oil?

Sodium is extremely reactive. It reacts vigorously with oxygen and moisture in the air and can even catch fire. To prevent this dangerous reaction, sodium is stored under kerosene oil, which keeps it away from air and water.

Q2. Write equations for the reactions of:

(i) iron with steam

3Fe(s) + 4H₂O(g) → Fe₃O₄(s) + 4H₂(g)

(ii) calcium and potassium with water

Ca(s) + 2H₂O(l) → Ca(OH)₂(aq) + H₂(g)
2K(s) + 2H₂O(l) → 2KOH(aq) + H₂(g) + Heat

Q3. Metals A, B, C, D and their reactions:

Metal	FeSO₄	CuSO₄	ZnSO₄	AgNO₃
A	No reaction	Displacement	—	—
B	Displacement	—	No reaction	—
C	No reaction	No reaction	No reaction	Displacement
D	No reaction	No reaction	No reaction	No reaction

(i) Which is the most reactive metal?

B — because it displaces iron from FeSO₄ (iron is higher in reactivity series).

(ii) What would you observe if B is added to CuSO₄ solution?

B displaces copper from CuSO₄. Blue colour of the solution fades, and a reddish-brown copper deposit forms on metal B.

(iii) Arrange metals A, B, C and D in decreasing order of reactivity.

B > A > C > D

Q4. Which gas is produced when dilute HCl is added to a reactive metal? Write the reaction of iron with dilute H₂SO₄.

Hydrogen gas (H₂) is produced.
Fe(s) + H₂SO₄(aq) → FeSO₄(aq) + H₂(g)↑

Q5. What happens when zinc is added to FeSO₄ solution?

Zinc is more reactive than iron, so it displaces iron from ferrous sulphate solution. The pale green colour of FeSO₄ fades and iron deposits on zinc.
Zn(s) + FeSO₄(aq) → ZnSO₄(aq) + Fe(s)

3.3 How Metals & Non-metals React (Ionic Bonds)

Metals tend to lose electrons to get a stable electron configuration (like noble gases). Non-metals tend to gain electrons. When a metal gives electrons to a non-metal, an ionic (electrovalent) compound is formed.

🔬 Formation of Sodium Chloride (NaCl)

Na (2,8,1) → loses 1 electron → Na⁺ (2,8)

Cl (2,8,7) → gains 1 electron → Cl⁻ (2,8,8)

Na⁺ and Cl⁻ attract each other → NaCl is formed

🔬 Formation of Magnesium Chloride (MgCl₂)

Mg (2,8,2) → loses 2 electrons → Mg²⁺ (2,8)

Each Cl (2,8,7) gains 1 electron → Cl⁻ (2,8,8)

1 Mg²⁺ + 2 Cl⁻ → MgCl₂ is formed

🧱 3.3.1 Properties of Ionic Compounds

Property	Description
Physical state	Solid; hard but brittle (break under pressure)
Melting & Boiling point	Very high (strong electrostatic forces need lots of energy to break)
Solubility	Generally soluble in water; insoluble in kerosene, petrol
Electrical conductivity	Conduct electricity in molten state and in aqueous solution; NOT in solid state

Ionic Compound	Melting Point (K)	Boiling Point (K)
NaCl	1074	1686
LiCl	887	1600
CaCl₂	1045	1900
CaO	2850	3120
MgCl₂	981	1685

❓ Questions (Section 3.3)

Q1(i). Write electron-dot structures for sodium, oxygen and magnesium.

Sodium (Na): 1 electron in outermost shell → Na·
Magnesium (Mg): 2 electrons in outermost shell → ·Mg·
Oxygen (O): 6 electrons in outermost shell → has 2 lone pairs + 2 unpaired electrons

Q1(ii). Show formation of Na₂O and MgO by electron transfer.

Na₂O: 2 Na atoms each lose 1 electron → 2 Na⁺. Oxygen gains 2 electrons → O²⁻. Combined: Na₂O.
MgO: Mg loses 2 electrons → Mg²⁺. Oxygen gains 2 electrons → O²⁻. Combined: MgO.

Q1(iii). What ions are present in Na₂O and MgO?

Na₂O contains Na⁺ and O²⁻. MgO contains Mg²⁺ and O²⁻.

Q2. Why do ionic compounds have high melting points?

Ionic compounds have strong electrostatic forces of attraction between oppositely charged ions (cation and anion). A large amount of energy is needed to break these forces. Therefore, ionic compounds have high melting and boiling points.

3.4 Occurrence & Extraction of Metals

🌍 Where Do Metals Come From?

The Earth's crust is the main source of metals. Natural substances containing metals are called minerals. Minerals from which metals can be profitably extracted are called ores. The unwanted impurities in an ore are called gangue.

Imp

Low reactivity metals (Au, Ag, Pt, Cu) → Found in FREE (native) state
Medium reactivity metals (Zn, Fe, Pb, Cu) → Found as oxides, sulphides or carbonates
High reactivity metals (K, Na, Ca, Mg, Al) → Never found free; always in compounds

⬇️ 3.4.3 Metals Low in Activity Series (Heating alone)

These metals are least reactive. Their oxides break down just by heating.

2HgS(s) + 3O₂(g) → 2HgO(s) + 2SO₂(g) [heating]

2HgO(s) → 2Hg(l) + O₂(g) [further heating]

2Cu₂S + 3O₂ → 2Cu₂O + 2SO₂

2Cu₂O + Cu₂S → 6Cu(s) + SO₂(g)

⬛ 3.4.4 Metals in the Middle — Roasting & Calcination

Roasting: Sulphide ores heated strongly in excess air → converts to oxide.

2ZnS(s) + 3O₂(g) → 2ZnO(s) + 2SO₂(g) (Roasting)

Calcination: Carbonate ores heated in limited air → converts to oxide.

ZnCO₃(s) → ZnO(s) + CO₂(g) (Calcination)

The metal oxide is then reduced by carbon (coke):

ZnO(s) + C(s) → Zn(s) + CO(g)

Thermit Reaction — Aluminium powder reduces iron oxide in a highly exothermic reaction. So much heat is released that iron comes out in the MOLTEN state! Used to weld railway tracks and cracked machine parts.

Fe₂O₃(s) + 2Al(s) → 2Fe(l) + Al₂O₃(s) + Heat

⬆️ 3.4.5 Metals at the Top — Electrolysis

Highly reactive metals (Na, Mg, Ca, Al) cannot be reduced by carbon — they have more affinity for oxygen than carbon. They are extracted by electrolytic reduction of their molten chlorides/oxides.

At cathode: Na⁺ + e⁻ → Na

At anode: 2Cl⁻ → Cl₂ + 2e⁻

🔋 3.4.6 Electrolytic Refining

Impure metals are purified by electrolysis:

Anode = Impure metal (dissolves)
Cathode = Thin strip of pure metal (pure metal deposits here)
Electrolyte = Solution of the metal's salt
Anode mud = Insoluble impurities that settle below the anode

❓ Questions (Section 3.4)

Q1. Define: (i) Mineral (ii) Ore (iii) Gangue

Mineral: Any element or compound that occurs naturally in the Earth's crust is called a mineral.
Ore: A mineral from which a particular metal can be extracted profitably is called an ore.
Gangue: The unwanted impurities (like soil, sand, etc.) mixed with the ore are called gangue.

Q2. Name two metals found in nature in the free state.

Gold (Au) and Silver (Ag)

Q3. What chemical process is used for obtaining a metal from its oxide?

Reduction — The metal oxide is reduced (by carbon/coke or by electrolysis) to obtain the pure metal. For example: ZnO + C → Zn + CO

3.5 Corrosion & Alloys

🦀 What is Corrosion?

When metals are exposed to moist air over time, their surface slowly gets eaten away. This is called corrosion.

Metal	What happens?	Product formed
Silver (Ag)	Reacts with sulphur in air	Black silver sulphide (Ag₂S)
Copper (Cu)	Reacts with moist CO₂ in air	Green basic copper carbonate
Iron (Fe)	Reacts with moist air (O₂ + H₂O)	Brown flaky rust (Fe₂O₃·xH₂O)

Imp Iron rusts only when BOTH oxygen and water are present. Dry air alone or water alone does not cause rusting.

🛡️ 3.5.1 Prevention of Corrosion

Painting / Oiling / Greasing — creates a barrier between metal and air/water
Galvanisation — coating iron/steel with a thin layer of zinc. Even if zinc coating breaks, it protects iron because zinc is more reactive and corrodes first.
Chrome plating / Anodising
Alloying — mixing metal with another substance to change its properties

🔀 Alloys

An alloy is a homogeneous mixture of two or more metals, or a metal and a non-metal. Alloys generally have lower electrical conductivity and lower melting point than the pure metals.

Alloy	Composition	Properties / Uses
Steel	Fe + C (0.05%)	Hard and strong; used in construction
Stainless Steel	Fe + Ni + Cr	Hard, does not rust; utensils, cutlery
Brass	Cu + Zn	Not a good conductor; decorative items
Bronze	Cu + Sn	Not a good conductor; statues, medals
Solder	Pb + Sn	Low melting point; welding wires
Amalgam	Metal + Mercury (Hg)	Special uses (dental fillings)
22-Carat Gold	Au (22 parts) + Cu or Ag (2 parts)	Used in jewellery (pure gold is too soft)

💡 The Iron Pillar of Delhi
The famous iron pillar near the Qutub Minar in Delhi is over 1600 years old and 8 metres tall, weighing 6 tonnes. It has NOT rusted! Ancient Indian metallurgists developed a special technique to protect iron from corrosion — a wonder even scientists today admire.

❓ Questions (Section 3.5)

Q1. In which cases will displacement reactions take place (ZnO, MgO, CuO heated with Zn, Mg, Cu)?

A more reactive metal displaces a less reactive metal from its oxide. Using the activity series (Mg > Zn > Cu):
✅ Mg + ZnO → MgO + Zn (reaction occurs)
✅ Mg + CuO → MgO + Cu (reaction occurs)
✅ Zn + CuO → ZnO + Cu (reaction occurs)
❌ Zn + MgO → No reaction (Zn less reactive than Mg)
❌ Cu + ZnO → No reaction
❌ Cu + MgO → No reaction

Q2. Which metals do not corrode easily?

Gold (Au), Platinum (Pt), and Silver (Ag) do not corrode easily because they are least reactive.

Q3. What are alloys?

An alloy is a homogeneous mixture of two or more metals, or a metal and a non-metal. It is made by melting the primary metal and dissolving other elements into it, then cooling. Example: Steel = Iron + Carbon.

✅ Solved Exercises

Q1. Which pair will give a displacement reaction?

(a) NaCl + Cu → No reaction (Cu less reactive than Na)
(b) MgCl₂ + Al → No reaction (Al less reactive than Mg)
(c) FeSO₄ + Ag → No reaction (Ag less reactive than Fe)
✅ (d) AgNO₃ + Cu → Cu displaces Ag
Cu(s) + 2AgNO₃(aq) → Cu(NO₃)₂(aq) + 2Ag(s)

Q2. Best method to prevent an iron frying pan from rusting?

✅ (c) Applying a coating of zinc (Galvanisation) is the best long-term method. However, painting and greasing can also work, so technically (d) all of the above is acceptable for general prevention.

Q3. An element forms a high-melting compound with oxygen that is also soluble in water. The element is likely to be:

✅ (a) Calcium — CaO has a high melting point. CaO + H₂O → Ca(OH)₂, which is soluble (lime water). Carbon and silicon form non-metallic (acidic) oxides. Iron oxide is insoluble in water.

Q4. Food cans are coated with tin and not zinc because:

✅ (c) Zinc is more reactive than tin. If zinc were used and the coating broke, zinc would react with food acids and could be harmful. Tin is less reactive and safer for food contact.

Q5. How can a hammer, battery, bulb, wires and switch help distinguish metals from non-metals?

(a) Using a hammer: Hit the sample. Metals are malleable — they flatten into sheets. Non-metals are brittle — they break into pieces.
Using the electrical circuit: Connect the sample between the circuit's terminals. If the bulb glows, it is a metal (conductor). If not, it is a non-metal (insulator).
(b) Usefulness: These tests are helpful but not perfect — graphite (non-metal) conducts electricity, and sodium (metal) is too soft to hammer. So both tests together are more reliable.

Q6. What are amphoteric oxides? Give two examples.

Metal oxides that react with both acids AND bases to form salt and water are called amphoteric oxides.
Examples: Al₂O₃ (aluminium oxide) and ZnO (zinc oxide).

Q7. Two metals that displace hydrogen from dilute acids, and two that do not.

Displace H₂: Zinc (Zn), Iron (Fe)
Do NOT displace H₂: Copper (Cu), Silver (Ag)

Q8. In electrolytic refining of metal M, what is the anode, cathode, and electrolyte?

Anode: Block of impure metal M
Cathode: Thin strip of pure metal M
Electrolyte: Aqueous solution of a salt of metal M (e.g., for copper: acidified CuSO₄)

Q9. Pratyush heats sulphur and collects the gas in an inverted test tube. (a) Action of gas on litmus paper? (b) Write the balanced equation.

The gas formed is sulphur dioxide (SO₂).
(a)(i) Dry litmus paper: No change — SO₂ alone does not affect dry litmus (it needs water to form acid).
(a)(ii) Moist litmus paper: Turns red — SO₂ dissolves in water to form sulphurous acid (H₂SO₃), which is acidic.
(b) S(s) + O₂(g) → SO₂(g)

Q10. State two ways to prevent rusting of iron.

1. Galvanisation — coating iron with a thin layer of zinc.
2. Painting or oiling — creating a physical barrier between iron and moist air.

Q11. What type of oxides are formed when non-metals combine with oxygen?

Non-metals form acidic oxides when they combine with oxygen. Example: SO₂ + H₂O → H₂SO₃ (sulphurous acid). Exception: CO and NO are neutral oxides (they do not form an acid or base with water).

Q12. Give reasons:

(a) Platinum, gold and silver are used to make jewellery.

These metals do not react with air, water, or acids easily. They are least reactive, so they retain their shine and beauty for a very long time.

(b) Na, K and Li are stored under oil.

These metals are highly reactive. They react vigorously with oxygen and moisture in air and may even catch fire. Kerosene oil keeps them away from air and water.

When aluminium is exposed to air, a thin, tough layer of aluminium oxide (Al₂O₃) forms on its surface. This oxide layer acts as a protective shield and prevents further reaction. So even though Al is reactive, this layer makes it safe for everyday use.

(d) Carbonate and sulphide ores are converted into oxides before extraction.

It is much easier to reduce a metal oxide than a sulphide or carbonate. Reduction of oxides by carbon (coke) is a simpler and more efficient process. So sulphides and carbonates are first converted into oxides by roasting and calcination respectively.

Q13. Why does lemon/tamarind juice clean tarnished copper vessels?

Tarnished copper is covered with a green layer of basic copper carbonate [CuCO₃·Cu(OH)₂]. Lemon and tamarind contain citric acid and tartaric acid respectively. These acids react with and dissolve the green layer, revealing the shiny copper surface below.

Q14. Differentiate between metals and non-metals based on chemical properties.

Property	Metals	Non-metals
Reaction with O₂	Form basic oxides	Form acidic oxides
Ion formation	Lose electrons → positive ions (cations)	Gain electrons → negative ions (anions)
React with acids	Displace H₂ from dilute acids	Do not react with dilute acids
React with H₂	Generally do not form hydrides	Form hydrides (e.g., HCl, H₂S)
Displacement	More reactive displaces less reactive	Cannot displace H₂ from acids

Q15. A goldsmith dipped gold bangles in a solution — they sparkled but became lighter. What solution did he use?

The goldsmith used Aqua Regia — a mixture of concentrated HCl and concentrated HNO₃ in ratio 3:1. Aqua Regia is the only solution that can dissolve gold. The outer gold layer dissolved in the solution, making the bangles lighter. The "clean sparkle" was the freshly exposed layer, but the net gold content was reduced — a trick to steal gold.

Q16. Why is copper used for hot water tanks and not steel (iron alloy)?

Copper does not react with hot water at all. Steel (iron alloy), on the other hand, can rust when exposed to hot water and moisture over time. Rusting weakens the tank and contaminates the water. Copper is also a better conductor of heat. Therefore, copper is preferred for hot water tanks.

📝 Quick Revision — What You Learnt

Metals are lustrous, malleable, ductile and good conductors of heat and electricity; solids at room temperature (except mercury).
Non-metals form acidic oxides; metals form basic oxides. Amphoteric oxides (Al₂O₃, ZnO) react with both.
The Activity Series lists metals in decreasing order of reactivity: K > Na > Ca > Mg > Al > Zn > Fe > Pb > [H] > Cu > Hg > Ag > Au.
Ionic compounds are formed when metals transfer electrons to non-metals; they have high melting points and conduct electricity only in molten/dissolved state.
Metals occur as free elements or in compounds (ores). Metallurgy = extraction + refining.
Corrosion (e.g., rusting) needs both oxygen AND water. Prevention: painting, galvanising, alloying.
An alloy is a homogeneous mixture of a metal with another metal or non-metal.

Download Free Mind Map PDF

This mind map contains all important topics of this chapter

[Download PDF Here]

Visit our Class 10 Science page for free mind maps of all Chapters