Class 10 Science Chapter 3: Metals and Non-Metals – पूरी जानकारी आसान भाषा में (Complete Guide 2025)

Introduction – दोस्तों, Elements की दुनिया में स्वागत!

आज हम Class 10 के super important chapter “Metals and Non-Metals” को बिल्कुल मजेदार तरीके से समझेंगे, अरे यार, क्या तुमने कभी सोचा है कि तुम्हारे घर का aluminum का बर्तन क्यों इतना light है और iron का gate इतना heavy? या फिर सोने के गहने क्यों कभी rust नहीं होते लेकिन लोहे पर जंग लग जाता है? ये सब Metals और Non-metals के अलग properties का कमाल है!

⏱️ Reading Time: 25-30 minutes 📚 NCERT Chapter 3 – 100% Coverage 🎯 Board Exam Ready Content

Table of Contents

1. Elements की दुनिया – Basic Introduction
2. Metals के Properties – Physical और Chemical
3. Non-Metals की Complete जानकारी
4. Activity Series और Reactivity
5. Extraction of Metals – धातु निकालना
6. Corrosion और Prevention Methods
7. Alloys – मिश्र धातु की पूरी जानकारी
8. Daily Life Applications
9. Important Chemical Reactions
10. Exam Questions और Memory Tricks

Elements की दुनिया – Basic Introduction {#elements-ki-duniya}

Periodic Table में Classification

118 Elements हैं, इनमें से:

• 78 Metals (लगभग 70%)
• 22 Non-metals (लगभग 18%)
• 18 Metalloids/Semi-metals (लगभग 12%)

Metals vs Non-Metals – Quick Comparison

Property	Metals	Non-Metals
State	Solid (except Mercury)	Solid, Liquid, Gas
Luster	Shiny/Metallic	Dull (except Iodine)
Conductivity	Good conductors	Poor conductors
Malleability	Can be hammered	Brittle (if solid)
Ductility	Can be drawn into wires	Cannot be drawn
Sound	Sonorous (ring when hit)	Not sonorous
Density	Usually high	Usually low
Melting Point	Usually high	Usually low

Real Life Examples

🔨 Metals Around Us:

• Copper: Electric wires में
• Aluminum: Cooking utensils में
• Iron: Construction में
• Gold: Jewelry में
• Silver: Coins और ornaments में

💨 Non-Metals Around Us:

• Oxygen: Breathing के लिए
• Carbon: Diamond, graphite के रूप में
• Nitrogen: Atmosphere में 78%
• Chlorine: Water purification में
• Sulfur: Matches में

Metals के Properties – Physical और Chemical {#metals-properties}

Physical Properties (भौतिक गुण)

1. Metallic Luster (चमक):

• Fresh cut करने पर shine करते हैं
• Example: Newly cut aluminum foil
• Exception: Lead (dull appearance)

2. Malleability (आघातवर्धनीयता):

• Hammer से पीटकर thin sheets बना सकते हैं
• Best Example: Gold (सबसे malleable)
• Use: Aluminum foil, gold leaf

3. Ductility (तन्यता):

• खींचकर thin wires बना सकते हैं
• Best Example: Gold (1g से 2km wire!)
• Use: Copper wires, silver wires

4. Electrical Conductivity:

Conductivity Order: Silver > Copper > Gold > Aluminum

Why Copper in wires? Silver expensive है, Copper cheaper और good conductor है

5. Thermal Conductivity:

• Heat को अच्छी तरह conduct करते हैं
• Daily Life: Cooking utensils metal के होते हैं

6. Sonorous Property:

• Hit करने पर metallic sound आती है
• Examples: School bells, temple bells

7. Density और Hardness:

• Most metals dense और hard होते हैं
• Exceptions:
  • Lithium: पानी पर float करता है
  • Sodium: Knife से cut हो जाता है

Chemical Properties (रासायनिक गुण)

1. Reaction with Oxygen:

Metal + Oxygen → Metal Oxide (Basic Oxide)

4Al + 3O₂ → 2Al₂O₃
2Cu + O₂ → 2CuO
4Fe + 3O₂ → 2Fe₂O₃ (Rusting)

Metal Oxides की Nature:

• Basic होते हैं
• Water में dissolve होकर alkaline solution बनाते हैं

Na₂O + H₂O → 2NaOH
CaO + H₂O → Ca(OH)₂

2. Reaction with Water:

Highly Reactive Metals:

2Na + 2H₂O → 2NaOH + H₂↑ (Vigorous reaction)
2K + 2H₂O → 2KOH + H₂↑ (Explosive!)
Ca + 2H₂O → Ca(OH)₂ + H₂↑ (Less vigorous)

Moderately Reactive:

Mg + H₂O → MgO + H₂↑ (Hot water/steam needed)
Zn + H₂O → ZnO + H₂↑ (Steam needed)

Less Reactive:

• Cu, Ag, Au → पानी के साथ react नहीं करते

3. Reaction with Acids:

Metal + Acid → Salt + Hydrogen Gas

Zn + 2HCl → ZnCl₂ + H₂↑
Mg + H₂SO₄ → MgSO₄ + H₂↑
2Al + 6HCl → 2AlCl₃ + 3H₂↑

H₂ Gas Test: Burning splinter के पास लाओ – “Pop” sound!

4. Displacement Reactions:

More Reactive Metal + Salt Solution → Less Reactive Metal + New Salt

Zn + CuSO₄ → ZnSO₄ + Cu↓
Fe + CuSO₄ → FeSO₄ + Cu↓
Cu + 2AgNO₃ → Cu(NO₃)₂ + 2Ag↓

Exceptional Cases (अपवाद)

Mercury (Hg):

• Room temperature पर liquid
• Poor conductor compared to other metals
• Highly toxic

Graphite (Carbon allotrope):

• Non-metal लेकिन electricity conduct करता है
• Soft और slippery

Non-Metals की Complete जानकारी {#non-metals-complete}

Physical Properties

1. Appearance:

• Generally dull (no metallic luster)
• Exception: Iodine (shiny purple crystals)

2. State at Room Temperature:

Solids: Carbon, Sulfur, Phosphorus, Iodine
Liquids: Bromine (only non-metal liquid)
Gases: Hydrogen, Oxygen, Nitrogen, Chlorine, etc.

3. Brittleness:

• Solid non-metals आसानी से break हो जाते हैं
• Example: Sulfur crystals easily breakable

4. Poor Conductors:

• Heat और electricity के poor conductors
• Exception: Graphite (carbon का allotrope)

5. Low Density:

• Generally light weight
• Exception: Diamond (carbon) – very hard

Chemical Properties

1. Reaction with Oxygen:

Non-metal + Oxygen → Non-metal Oxide (Acidic/Neutral)

C + O₂ → CO₂ (Acidic oxide)
S + O₂ → SO₂ (Acidic oxide)
4P + 5O₂ → 2P₂O₅ (Acidic oxide)

Non-metal Oxides:

• Acidic होते हैं
• Water के साथ acids बनाते हैं

CO₂ + H₂O → H₂CO₃ (Carbonic acid)
SO₂ + H₂O → H₂SO₃ (Sulphurous acid)

2. Reaction with Hydrogen:

Cl₂ + H₂ → 2HCl
S + H₂ → H₂S
N₂ + 3H₂ → 2NH₃ (High temperature, pressure, catalyst)

3. Reaction with Metals:

Na + Cl₂ → 2NaCl
2Al + 3Cl₂ → 2AlCl₃
Mg + S → MgS

Important Non-Metals Detail में

💎 Carbon:

• Allotropes: Diamond, Graphite, Fullerenes
• Diamond: Hardest natural substance
• Graphite: Soft, conducts electricity
• Uses: Pencils, jewelry, industrial cutting

🌬️ Oxygen:

• Essential: Life के लिए जरूरी
• Combustion: Burning में supporter
• Industrial: Steel making में

💨 Nitrogen:

• 78% atmosphere में
• Inert: कम reactive
• Uses: Fertilizers, explosives

☠️ Chlorine:

• Poisonous gas
• Disinfectant: Water purification
• Bleaching: Paper, textiles

Activity Series और Reactivity {#activity-series-reactivity}

Reactivity Series (क्रियाशीलता श्रेणी)

Most Reactive से Least Reactive:

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

Memory Trick: “King Sodium Called Magnesium; Aluminum Zinc Iron Lead; Hydrogen Copper Mercury Silver Gold”

या फिर: “केसरिया कपड़े में अजीब ज़िन्दगी फैली पड़ी है; हर कुमार मेरे साथ गया”

Reactivity के Based पर Groups

🔥 Most Reactive (K, Na, Ca):

• Stored in kerosene oil
• React violently with water
• Cannot be extracted by carbon reduction

⚡ Moderately Reactive (Mg, Al, Zn, Fe):

• React with hot water/steam
• Can be extracted by carbon reduction
• Form protective oxide layers

💤 Less Reactive (Pb, Cu, Hg):

• Don’t react with water
• React with strong acids only
• Easy to extract from ores

✨ Least Reactive (Ag, Au):

• Don’t react with most chemicals
• Found in free state in nature
• Called “Noble Metals”

Displacement Reactions Rules

Rule: More reactive metal, less reactive metal को displace करता है

Examples:

Zn + CuSO₄ → ZnSO₄ + Cu (होगा ✅)
Cu + ZnSO₄ → No Reaction (नहीं होगा ❌)

Fe + CuSO₄ → FeSO₄ + Cu (होगा ✅)
Cu + FeSO₄ → No Reaction (नहीं होगा ❌)

Visual Observation:

• Blue CuSO₄ solution colorless हो जाता है
• Reddish-brown copper metal deposit होता है

Extraction of Metals – धातु निकालना {#extraction-metals}

Occurrence of Metals in Nature

Free State में मिलने वाले (Least Reactive):

• Gold, Silver, Platinum
• Why? ये chemically inert हैं

Combined State में मिलने वाले:

• सभी other metals
• Forms: Oxides, Sulfides, Carbonates, Chlorides

Common Ores (अयस्क)

Metal	Ore Name	Chemical Formula
Aluminum	Bauxite	Al₂O₃.2H₂O
Iron	Haematite	Fe₂O₃
	Magnetite	Fe₃O₄
Copper	Copper pyrites	CuFeS₂
	Malachite	CuCO₃.Cu(OH)₂
Zinc	Zinc blende	ZnS
	Calamine	ZnCO₃
Lead	Galena	PbS
Silver	Silver glance	Ag₂S

Steps in Metallurgy

1. Concentration/Enrichment:

• Ore से unwanted materials (gangue) remove करना
• Methods:
  • Gravity Separation: Heavy particles settle
  • Magnetic Separation: Magnetic ores को separate करना
  • Froth Floatation: Sulfide ores के लिए

2. Conversion to Oxide:

• Most extraction methods oxides से easier हैं
• Roasting: Sulfide ores को heat करके oxide बनाना

2ZnS + 3O₂ → 2ZnO + 2SO₂

• Calcination: Carbonate ores को heat करना

ZnCO₃ → ZnO + CO₂

3. Reduction of Oxide:

• Oxide से pure metal निकालना

Extraction Methods (Reactivity Based)

🔥 Highly Reactive Metals (K, Na, Ca, Mg, Al):

• Method: Electrolysis of molten salts
• Why? Carbon भी इन्हें reduce नहीं कर सकता

Aluminum Extraction:

Al₂O₃ → 2Al + 3/2 O₂ (Electrolysis)

• Bauxite + Cryolite (Na₃AlF₆) mixture
• High temperature needed (1000°C)
• Expensive process (lots of electricity)

⚡ Moderately Reactive (Zn, Fe, Pb, Cu):

• Method: Carbon reduction
• Principle: Carbon, metal oxide को reduce करता है

Iron Extraction (Blast Furnace):

Fe₂O₃ + 3CO → 2Fe + 3CO₂

Process में steps:

11. Charge: Iron ore + Coke + Limestone
12. Hot air bottom से blast करते हैं

1. Reactions:

• C + O₂ → CO₂
  CO₂ + C → 2CO (Reducing agent)
  Fe₂O₃ + 3CO → 2Fe + 3CO₂

14. Limestone impurities remove करता है

Zinc Extraction:

ZnO + C → Zn + CO

💤 Less Reactive (Cu, Hg):

• Simple heating भी sufficient हो सकती है

2HgS + 3O₂ → 2HgO + 2SO₂
2HgO → 2Hg + O₂

Refining (शुद्धीकरण)

1. Electrolytic Refining:

• Anode: Impure metal
• Cathode: Pure metal strip
• Electrolyte: Metal salt solution

Copper Refining:

• Impure copper anode पर, pure copper cathode पर deposit होता है
• Impurities settle down as “anode mud”

2. Other Methods:

• Distillation: Mercury के लिए
• Liquation: Tin के लिए
• Zone Refining: Semiconductors के लिए

Corrosion और Prevention Methods {#corrosion-prevention}

Corrosion क्या है?

Definition: Metals का atmospheric gases (O₂, CO₂, H₂O vapor) के साथ slow reaction जिससे metal degrade हो जाता है।

Most Common: Rusting of Iron

Rusting की Chemistry

Conditions Required:

15. Oxygen (O₂)
16. Water/Moisture (H₂O)
17. Time

Chemical Process:

4Fe + 3O₂ + 2xH₂O → 2Fe₂O₃.xH₂O (Rust)
(Iron)           → (Hydrated Iron(III) oxide)

Rust:

• Color: Reddish-brown
• Nature: Flaky, porous
• Problem: Volume में increase, metal weak हो जाता है

Factors Affecting Corrosion

Accelerating Factors:

18. Moisture: High humidity areas में ज्यादा rust
19. Salt: Sea areas में faster corrosion
20. Acid Rain: SO₂, NO₂ से बना acid
21. Temperature: High temperature = faster reaction

Experiments to Show Conditions:

• Test Tube 1: Iron nails + dry air → No rust
• Test Tube 2: Iron nails + water (boiled, no O₂) → No rust
• Test Tube 3: Iron nails + air + water → Rust forms ✅

Prevention Methods

1. Physical Barrier Methods:

🎨 Painting:

• Barrier बनाता है air और metal के बीच
• Use: Cars, furniture, buildings
• Maintenance: Regular repainting needed

🛢️ Oiling/Greasing:

• Thin film of oil prevents air contact
• Use: Machine parts, tools
• Advantage: Easy application

2. Chemical Methods:

⚡ Galvanizing:

• Iron पर zinc की thin coating
• Process: Hot zinc bath में dipping
• Advantage: Zinc corrodes first, iron बचा रहता है
• Use: Water tanks, pipes, roofing sheets

🥈 Electroplating:

• Electrolysis से एक metal की दूसरे पर coating
• Examples:
  • Chrome plating (cars, taps)
  • Silver plating (jewelry)
  • Gold plating (electronics)

3. Alloying:

• Pure metals की बजाय alloys use करना
• Stainless Steel: Iron + Chromium + Nickel
• Advantage: Corrosion resistant, strong

4. Sacrificial Protection:

• More reactive metal attach करके
• Example: Zinc blocks ship के hull पर
• Zinc corrodes, iron safe रहता है

Real Life Applications

🚗 Automobile Industry:

• Multiple coatings: Primer + Paint + Clear coat
• Galvanized parts
• Stainless steel exhaust

🏗️ Construction:

• Galvanized iron sheets
• Stainless steel reinforcement
• Protective paints

⚓ Marine Applications:

• Special anti-corrosive paints
• Sacrificial anodes
• Regular maintenance schedules

Alloys – मिश्र धातु की पूरी जानकारी {#alloys-complete}

Alloy क्या होते हैं?

Definition: दो या अधिक metals (या metal + non-metal) का homogeneous mixture

Formation: Molten state में mix करके cooling

Purpose: Pure metals की properties improve करना

Why Alloys Better than Pure Metals?

🔧 Pure Metals की Problems:

• Too Soft: Pure gold easily deforms
• Corrosion: Pure iron rusts easily
• Low Strength: Pure aluminum not strong enough
• High Cost: Pure metals expensive

✨ Alloys के Advantages:

• Increased Hardness: Strong होते हैं
• Corrosion Resistance: Better protection
• Desirable Properties: Specific needs के लिए
• Economic: Cost-effective

Important Alloys और Properties

🥇 Steel (लोहे के Alloys):

Type	Composition	Properties	Uses
Carbon Steel	Fe + 0.3-1.5% C	Hard, strong	Tools, machinery
Stainless Steel	Fe + Cr + Ni	Rust-resistant	Utensils, medical
Manganese Steel	Fe + Mn	Very hard	Railway tracks

🥈 Copper Alloys:

Alloy	Composition	Properties	Uses
Brass	Cu + Zn	Golden color, malleable	Decorative, instruments
Bronze	Cu + Sn	Hard, corrosion-resistant	Statues, coins
German Silver	Cu + Zn + Ni	Silver-like appearance	Utensils, jewelry

🥉 Aluminum Alloys:

Duralumin: Al + Cu + Mg + Mn

• Properties: Light weight + High strength
• Uses: Aircraft construction, automotive

Magnalium: Al + Mg

• Properties: Very light, strong
• Uses: Balance beams, optical instruments

🏅 Precious Metal Alloys:

Gold Alloys:

• 22 Carat: 22/24 = 91.7% gold + Cu/Ag
• 18 Carat: 18/24 = 75% gold + other metals
• Purpose: Pure gold too soft for jewelry

Silver Alloys:

• Sterling Silver:5% Ag + 7.5% Cu
• Coin Silver: 90% Ag + 10% Cu

Special Purpose Alloys

🔥 High Temperature Alloys:

• Nichrome: Ni + Cr + Fe
• Use: Heating elements (heaters, toasters)
• Property: High melting point, doesn’t oxidize

🌡️ Low Melting Point Alloys:

• Solder: Pb + Sn (50:50)
• Use: Joining electrical wires
• Wood’s Metal: Bi + Pb + Sn + Cd (melts at 70°C)

🦷 Dental Alloys:

• Amalgam: Hg + Ag + Sn + Cu
• Use: Dental fillings
• Property: Hardens at body temperature

Alloy Formation Process

1. Melting:

• Constituent metals को high temperature पर melt करना
• Different melting points का problem

2. Mixing:

• Molten metals को proper ratio में mix करना
• Stirring for homogeneous mixture

3. Cooling:

• Controlled cooling for desired crystal structure
• Quenching for rapid cooling (hardness)
• Annealing for slow cooling (toughness)

4. Processing:

• Rolling: Sheets बनाने के लिए
• Drawing: Wires बनाने के लिए
• Forging: Complex shapes

Memory Tricks for Alloys

Steel Types: “Carbon Creates Strength, Stainless Stops Rust, Manganese Makes Hardness”

Copper Alloys: “Brass has Zinc shine, Bronze has Tin time, German silver is Nickel fine”

Carat System: “24 Carat Pure, 22 Carat Sure, 18 Carat Store, 14 Carat Poor”

Daily Life Applications {#daily-life-applications}

Kitchen में Metals/Non-Metals

👩‍🍳 Cooking Utensils:

Material	Properties	Uses	Why This Choice?
Aluminum	Light, good conductor	Pressure cookers, pans	Light weight + heat conduction
Stainless Steel	Rust-resistant	Utensils, sink	Hygiene + durability
Copper	Excellent conductor	Bottom of pans	Even heat distribution
Iron	Cheap, strong	Tawa, kadhai	Traditional, adds iron to food

🔥 Gas Stove Components:

• Brass: Burner (doesn’t react with gas)
• Steel: Body (strength)
• Rubber: Pipe (flexibility)

Construction Industry

🏗️ Building Materials:

Steel (Fe alloys):

• Reinforcement bars: Concrete में strength
• Beams and columns: Load bearing
• Roofing sheets: Galvanized iron

Aluminum:

• Window frames: Light weight, no rust
• Roofing: Reflects heat

Copper:

• Electrical wiring: Best conductor after silver
• Plumbing: Antimicrobial properties

Transportation

🚗 Automobile Industry:

Engine Parts:

• Steel alloys: Strength for engine block
• Aluminum: Light weight pistons
• Copper: Radiator (heat exchange)

Body:

• Steel: Safety and strength
• Aluminum: Fuel efficiency (lighter)
• Plastics (non-metals): Interior parts

✈️ Aviation:

• Duralumin: Aircraft body (light + strong)
• Titanium alloys: Jet engines (high temp resistance)
• Carbon fiber: Modern aircraft parts

Electronics Industry

💻 Computer Components:

• Silicon (metalloid): Semiconductors, chips
• Copper: Circuit board connections
• Gold: High-end connectors (doesn’t corrode)
• Silver: High-frequency applications

📱 Mobile Phones:

• Aluminum: Body (light, strong, heat dissipation)
• Copper: Internal wiring
• Gold: Connector pins
• Rare earth metals: Speakers, vibration

Medical Field

🏥 Medical Instruments:

• Stainless Steel: Surgical instruments (sterilizable)
• Titanium: Bone implants (biocompatible)
• Gold: Dental work (doesn’t react with saliva)
• Mercury: Thermometers (liquid at room temp)

💊 Pharmaceuticals:

• Magnesium: Antacids
• Iron: Anemia treatment
• Iodine: Antiseptic
• Silver: Antimicrobial coatings

Important Chemical Reactions {#important-reactions}

Metal Reactions – Complete List

1. Metal + Oxygen:

2Mg + O₂ → 2MgO (Bright white light)
4Al + 3O₂ → 2Al₂O₃ (Protective layer)
2Cu + O₂ → 2CuO (Black copper oxide)
4Fe + 3O₂ → 2Fe₂O₃ (Rusting – slow)

2. Metal + Water/Steam:

2Na + 2H₂O → 2NaOH + H₂↑ (Vigorous, floats)
Ca + 2H₂O → Ca(OH)₂ + H₂↑ (Less vigorous)
Mg + H₂O → MgO + H₂↑ (Hot water needed)
Zn + H₂O → ZnO + H₂↑ (Steam needed)
3Fe + 4H₂O → Fe₃O₄ + 4H₂↑ (Red hot iron + steam)

3. Metal + Acid:

Zn + 2HCl → ZnCl₂ + H₂↑
Mg + H₂SO₄ → MgSO₄ + H₂↑
2Al + 6HCl → 2AlCl₃ + 3H₂↑
Fe + 2HCl → FeCl₂ + H₂↑

Note: Cu, Ag, Au don’t react with dilute acids

4. Displacement Reactions:

Zn + CuSO₄ → ZnSO₄ + Cu↓ (Blue to colorless)
Fe + CuSO₄ → FeSO₄ + Cu↓ (Blue to green)
Cu + 2AgNO₃ → Cu(NO₃)₂ + 2Ag↓ (Colorless to blue)
Pb + CuSO₄ → PbSO₄ + Cu↓

Non-Metal Reactions

1. Non-metal + Oxygen:

C + O₂ → CO₂ (Complete combustion)
2C + O₂ → 2CO (Incomplete combustion)
S + O₂ → SO₂ (Pungent smell)
4P + 5O₂ → 2P₂O₅ (White fumes)

2. Non-metal + Hydrogen:

Cl₂ + H₂ → 2HCl (Hydrogen chloride gas)
Br₂ + H₂ → 2HBr (Hydrogen bromide)
S + H₂ → H₂S (Rotten egg smell)

3. Non-metal + Metal:

2Na + Cl₂ → 2NaCl (Vigorous reaction)
Mg + Cl₂ → MgCl₂ (White smoke)
2Al + 3Cl₂ → 2AlCl₃ (Heat + light produced)

Oxide Reactions

Metal Oxides (Basic):

Na₂O + H₂O → 2NaOH (Strongly basic)
CaO + H₂O → Ca(OH)₂ (Slaked lime)
MgO + H₂O → Mg(OH)₂ (Milk of magnesia)

 

Non-metal Oxides (Acidic):

CO₂ + H₂O → H₂CO₃ (Carbonic acid)
SO₂ + H₂O → H₂SO₃ (Sulphurous acid)
SO₃ + H₂O → H₂SO₄ (Sulphuric acid)
P₂O₅ + 3H₂O → 2H₃PO₄ (Phosphoric acid)

Amphoteric Oxides:

Al₂O₃ + 6HCl → 2AlCl₃ + 3H₂O (Acts as base)
Al₂O₃ + 2NaOH → 2NaAlO₂ + H₂O (Acts as acid)

ZnO + 2HCl → ZnCl₂ + H₂O (Acts as base)
ZnO + 2NaOH → Na₂ZnO₂ + H₂O (Acts as acid)

Extraction Reactions

Carbon Reduction:

ZnO + C → Zn + CO
PbO + C → Pb + CO
2CuO + C → 2Cu + CO₂
Fe₂O₃ + 3CO → 2Fe + 3CO₂ (Blast furnace)

Self Reduction (Auto-reduction):

Cu₂S + 2Cu₂O → 6Cu + SO₂ (Copper extraction)
2PbS + 3O₂ → 2PbO + 2SO₂
PbS + 2PbO → 3Pb + SO₂

Electrolytic Reactions:

2Al₂O₃ → 4Al + 3O₂ (At cathode: Al³⁺ + 3e⁻ → Al)
2NaCl → 2Na + Cl₂ (At cathode: Na⁺ + e⁻ → Na)

Exam Questions और Memory Tricks {#exam-questions-tricks}

Previous Years’ Important Questions

📝 1 Mark Questions:

1. Name two metals which are found in free state in nature.

• Answer: Gold and Silver

1. Which gas is produced when metals react with acids?

• Answer: Hydrogen gas

1. What is the chemical name of rust?

• Answer: Hydrated Iron(III) oxide (Fe₂O₃.xH₂O)

1. Name the process of depositing a layer of any desired metal on another material by means of electricity.

• Answer: Electroplating

1. Which metal is used for galvanizing iron?

• Answer: Zinc

📝 2 Marks Questions:

1. State two ways to prevent the rusting of iron.

• Answer:
  • Galvanizing (coating with zinc)
  • Painting (creating barrier from air and moisture)

1. Why is sodium kept immersed in kerosene oil?

• Answer: Sodium is highly reactive and reacts vigorously with oxygen and water vapor in air, so it’s stored in kerosene to prevent contact with air.

1. Write the electron-dot structures for sodium, oxygen and magnesium.

• Answer:
  • Na: Na• (1 valence electron)
  • O: •Ö• (6 valence electrons)
  • Mg: Mg•• (2 valence electrons)

📝 3 Marks Questions:

1. An element A burns with golden flame in air. It reacts with another element B, atomic number 17 to give a product C. An aqueous solution of product C on electrolysis gives a compound D and liberates hydrogen. Identify A, B, C and D.

• Answer:
  • A = Sodium (Na) – golden flame
  • B = Chlorine (Cl) – atomic number 17
  • C = Sodium chloride (NaCl)
  • D = Sodium hydroxide (NaOH)

1. Write equations for the reactions of:

• (i) Iron with steam
• (ii) Calcium and potassium with water

• Answer:
• (i) 3Fe + 4H₂O → Fe₃O₄ + 4H₂
  (ii) Ca + 2H₂O → Ca(OH)₂ + H₂
  2K + 2H₂O → 2KOH + H₂

📝 5 Marks Questions:

1. What are alloys? Why are alloys prepared? Give the composition and uses of:
   • (a) Brass (b) Bronze (c) Stainless steel

• Answer:
  • Alloys: Homogeneous mixture of two or more metals or a metal and non-metal
  • Why prepared: To improve properties like hardness, strength, corrosion resistance
  • (a) Brass: Cu + Zn; Musical instruments, decorative items
  • (b) Bronze: Cu + Sn; Medals, statues, coins
  • (c) Stainless Steel: Fe + Cr + Ni; Utensils, surgical instruments

Memory Tricks और Mnemonics

🧠 Reactivity Series: “Please Send Charlie My Aunt Zanzibar In Lead Heavy Copper Silver Gold”

• Potassium, Sodium, Calcium, Magnesium, Aluminum, Zinc, Iron, Lead, Hydrogen, Copper, Silver, Gold

🧠 Properties of Metals: “My Metallic Dreams Come True Suddenly”

• Malleability, Metallic luster, Ductility, Conductivity, Thermal conductivity, Sonorous

🧠 Galvanizing Process: “Zinc Protects Iron From Rust”

• Zinc coating on iron prevents rusting

🧠 Noble Metals: “Silver And Gold” – don’t react easily

🧠 Alloy Compositions:

• Brass = Copper + Zinc (“Brass has Z for Zinc”)
• Bronze = Copper + Tin (“Bronze has T for Tin”)
• Steel = Iron + Carbon (“Steel is Strong with Carbon”)

Quick Revision Points

⚡ Must Remember Facts:

1. Only liquid metal at room temperature: Mercury
2. Only liquid non-metal at room temperature: Bromine
3. Most malleable metal: Gold
4. Most ductile metal: Gold
5. Best conductor of electricity: Silver
6. Lightest metal: Lithium
7. Hardest natural substance: Diamond
8. Most abundant metal in earth’s crust: Aluminum
9. Most abundant non-metal in atmosphere: Nitrogen (78%)
10. Metal that can be cut with knife: Sodium, Potassium

⚡ Chemical Formulas to Remember:

• Rust: Fe₂O₃.xH₂O
• Bauxite: Al₂O₃.2H₂O
• Limestone: CaCO₃
• Dolomite: CaCO₃.MgCO₃
• Galena: PbS
• Zinc blende: ZnS

Practice Questions for Board Exam

🎯 Very Important Questions:

1. Activity-based Question: Design an activity to show that metal oxides are basic in nature.
2. HOTS Question: A metal M does not liberate hydrogen from acids but reacts with oxygen to give a black color product. Identify M and black product. Write the reaction.
3. Assertion-Reasoning:

• Assertion: Aluminum is used for making cooking utensils.
• Reason: Aluminum is a good conductor of heat.

1. Case Study: A student took four metals P, Q, R, S and put them in CuSO₄ solution. Only P and R displaced copper. When P was put in R’s salt solution, no reaction occurred. Arrange them in order of reactivity.

Diagram-based Questions

🔬 Important Diagrams to Practice:

1. Activity to show H₂ gas evolution:

• Test tube with metal + acid
• Gas collection setup
• Burning splinter test

1. Electrolytic refining of copper:

• Anode: Impure copper
• Cathode: Pure copper
• Electrolyte: CuSO₄ solution

1. Rusting experiment:

• Three test tubes showing different conditions
• Only tube with air + water shows rust

1. Blast furnace diagram:

• Different zones and their temperatures
• Raw materials input and products output

Last-Minute Tips

📚 Night Before Exam:

1. Revise reactivity series – Most questions come from this
2. Practice balancing equations – Easy marks
3. Remember alloy compositions – Frequently asked
4. Corrosion prevention methods – Sure shot question
5. Extraction methods based on reactivity

✍️ During Exam:

1. Read questions carefully – displacement vs replacement
2. Write balanced equations – Half marks for unbalanced
3. Use proper chemical formulas – H₂O not H2O
4. Draw neat diagrams – Label all parts
5. Manage time – Don’t spend too much on one question

Summary और Final Notes

Chapter 3 Complete Summary

🔑 Key Concepts Covered:

1. Classification: 78 metals, 22 non-metals, 18 metalloids
2. Properties: Physical और chemical properties detailed comparison
3. Reactivity Series: K to Au arrangement और applications
4. Extraction: Different methods based on reactivity
5. Corrosion: Rusting mechanism और prevention
6. Alloys: Important compositions और uses

🎯 Most Important for Boards:

• Reactivity series और its applications
• Displacement reactions
• Extraction of aluminum और iron
• Rusting और prevention methods
• Important alloys और their uses
• Chemical equations balancing

📈 Scoring Strategy:

• Definitions: Clear और precise definitions (1-2 marks)
• Equations: Balanced chemical equations (2-3 marks)
• Diagrams: Well-labeled diagrams (3-5 marks)
• Applications: Real-life examples (2-3 marks)
• Reasoning: Why questions with proper logic (3-5 marks)

Final Message

दोस्तों, Metals and Non-metals chapter science की foundation है। ये concepts आगे chemistry में बहुत काम आएंगे। Practice करते रहो, equations को समझकर याद करो, और real-life examples से connect करो।

All the Best for your Board Exams! 🌟

📞 Need Help?

• Practice more numerical problems
• Make flash cards for formulas
• Group study for better understanding
• Solve previous year papers

🏆 Success Mantra: “Practice Perfect Makes Perfect Performance!”