Login / Register
Follow Us
0
0
Register Free!
Register Free!
Online Mock Tests & Exam Preparation | Target Exams
Select Medium / माध्यम चुनें:
Eng (English) Hindi (हिन्दी)
ICSE • Class 7 • Science • Ch 13
Estimated Time: 45 Mins
Study Progress: In Progress

Metals and Non-Metals

In ICSE Class 7 Science (Chemistry), "Metals and Non-Metals" provides an authoritative, experimentally validated master study guide investigating the comparative physical and chemical properties, reactivity series, alloys, corrosion, and industrial applications of metallic and non-metallic elements. This comprehensive chapter explores Physical Properties (Metals: metallic luster, malleability [hammered into thin foil], ductility [drawn into fine wire], electrical conductivity [copper, aluminum], thermal conductivity [silver, copper], sonorous ringing sound, high melting/boiling points, high density; Exceptions: Mercury is liquid at room temperature; Sodium and Potassium are soft metals sliced with a butter knife with low densities; Non-Metals: non-lustrous [exception: Iodine crystals, Diamond], brittle/non-malleable, non-ductile, non-sonorous, thermal and electrical insulators; Exceptions: Carbon as Graphite is an excellent electrical conductor; Bromine is a liquid non-metal; Diamond is the hardest natural substance known with high thermal conductivity), Chemical Properties of Metals (Reaction with atmospheric Oxygen forming basic metal oxides: $2Mg + O_2 \to 2MgO$; Reaction of active metals with cold water: $2Na + 2H_2O \to 2NaOH + H_2 \uparrow$; Reaction with dilute mineral acids [$HCl, H_2SO_4$] releasing Hydrogen gas: $Zn + 2HCl \to ZnCl_2 + H_2 \uparrow$; Reaction with steam: $3Fe + 4H_2O \to Fe_3O_4 + 4H_2 \uparrow$), Chemical Properties of Non-Metals (Reaction with Oxygen forming acidic/neutral non-metal oxides: $C + O_2 \to CO_2, S + O_2 \to SO_2$; Non-metals do NOT displace hydrogen from dilute acids), The Metal Reactivity Series ($K > Na > Ca > Mg > Al > Zn > Fe > Pb > [H] > Cu > Hg > Ag > Au$), Alloys (Definition: homogeneous solid mixture of two or more metals or a metal and non-metal; Brass [$Cu + Zn$], Bronze [$Cu + Sn$], Stainless Steel [$Fe + Cr + Ni + C$], Duralumin [$Al + Cu + Mg + Mn$]; Superior properties: increased strength, resistance to corrosion, lower melting point), and Corrosion & Rusting Prevention aligned with the 2026–27 CISCE ICSE curriculum.

Take Chapter CBT Test View All Chapters
Overview Core Concepts Formulas & Reactions Summary Self Check Take MCQ Test

Why Did a 1,600-Year-Old Iron Pillar in Delhi Stand in Pouring Monsoon Rains and Blistering Desert Heat for Centuries Without a Single Flake of Rust?

In the courtyard of the Qutub Minar complex in New Delhi stands a towering, six-ton wrought-iron pillar forged during the Gupta Empire in the 4th century CE. For over 1,600 consecutive years, this ancient monument has stood completely outdoors—battered by torrential monsoon rainstorms, blazing tropical sunlight, and toxic modern smog. Yet while modern steel cars rust into scrap metal within ten years, the Iron Pillar of Delhi has virtually ZERO RUST! How did ancient Indian metallurgists outsmart the laws of chemical corrosion sixteen centuries before modern chemistry was born? Metallurgical electron microscopes revealed their secret: ancient blacksmiths did not use limestone flux; they hammered high-phosphorus iron with charcoal, creating an ultra-thin, passive protective crystalline armor of misawite and iron hydrogen phosphate hydrate that permanently seals the metal from atmospheric oxygen and moisture! What is the difference between a Metal and a Non-Metal? Why does mixing copper and zinc produce golden Brass? Let's master metals and non-metals.

Why This Chapter Matters

Metals and non-metals form the physical infrastructure of human society. Aluminum alloys frame commercial airliners, copper wires conduct nationwide electric grids, silicon semiconductors drive microprocessors, and stainless steel ensures sterile surgical instruments. Mastering the reactivity series ($K$ to $Au$) and alloy formulations is vital for ICSE chemistry and engineering.

Before You Begin (Prerequisites)

  • Elements and atomic structure from Chapters 10 and 11.
  • Valence electrons and valency rules from Chapter 12.
  • Basic physical states and phase changes.

What You Will Learn (Core Objectives)

  • Compare metals and non-metals across 8 physical properties and identify all key chemical exceptions.
  • Explain why metals form basic oxides while non-metals form acidic or neutral oxides.
  • Write balanced chemical equations for reactions of metals with oxygen, water, and dilute acids.
  • Arrange common metals in the order of the Reactivity Series and predict displacement reactions.
  • Define an alloy and state the composition and engineering utility of Brass, Bronze, and Stainless Steel.
  • Analyze the chemical mechanism of corrosion and explain methods of rust prevention.

Chapter Roadmap & Progression

1 1. Physical Properties & Famous Exc...
2 2. Chemical Properties: Metals vs N...
3 3. The Metal Reactivity Series
4 4. Alloys: Compositions & Engineeri...

Complete Concept Guide (100% Curriculum Coverage)

1. Physical Properties & Famous Exceptions

Understand
A. Metals: General Characteristics & Exceptions:
  • Malleability: Can be hammered into ultra-thin sheets (Gold and Silver are the most malleable; gold leaf is only $0.0001\text{ mm}$ thick!).
  • Ductility: Can be drawn into thin wires (One gram of gold can be drawn into a $2\text{ km}$ fine wire!).
  • Luster & Hardness: Shiny metallic luster; generally hard.
    • Exceptions: Sodium ($Na$) and Potassium ($K$) are so soft they can be sliced like butter with a dull table knife!
    • Exception: Mercury ($Hg$) is the only metal that is a liquid at room temperature ($25^\circ\text{C}$). (Gallium and Cesium melt in the palm of your hand at $30^\circ\text{C}$!).
  • Electrical & Thermal Conductivity: Excellent conductors (Silver is #1, followed by Copper and Aluminum).
  • Sonority: Emit a deep, ringing musical tone when struck (used in church and temple bells).
B. Non-Metals: General Characteristics & Exceptions:
  • Generally dull, soft, brittle solids or gases.
  • Exception (Liquid non-metal): Bromine ($Br_2$) is the only non-metal that is a reddish-brown liquid at room temperature.
  • Exception (Luster): Iodine crystals and Diamond exhibit brilliant luster.
  • Exception (Hardness): Diamond (an allotrope of carbon) is the hardest natural substance known on Earth!
  • Exception (Electrical Conductor): Graphite (an allotrope of carbon) has free delocalized electrons, making it an excellent electrical conductor used in battery dry cell electrodes!

2. Chemical Properties: Metals vs Non-Metals

Chemical Properties
A. Reaction with Oxygen:
  • Metals form Basic Oxides: $$2Mg + O_2 \to 2MgO \quad (MgO + H_2O \to Mg(OH)_2, \text{ turns red litmus blue!})$$
  • Non-Metals form Acidic Oxides: $$C + O_2 \to CO_2 \quad (CO_2 + H_2O \to H_2CO_3, \text{ turns blue litmus red!})$$ $$S + O_2 \to SO_2 \quad (SO_2 + H_2O \to H_2SO_3, \text{ Sulfurous acid})$$
B. Reaction with Water:
  • Active alkali metals react violently with cold water: $$2Na + 2H_2O \to 2NaOH + H_2 \uparrow + \text{Heat (catches fire!)}$$
  • Magnesium reacts with hot water: $Mg + 2H_2O \to Mg(OH)_2 + H_2 \uparrow$.
  • Iron reacts only with red-hot steam: $3Fe + 4H_2O(g) \to Fe_3O_4 + 4H_2 \uparrow$.
  • Non-metals do NOT react with water to release hydrogen gas.
C. Reaction with Dilute Acids:

Metals above hydrogen in the reactivity series displace hydrogen from dilute $HCl$ or $H_2SO_4$:

$$\mathbf{\text{Metal} + \text{Dilute Acid} \to \text{Metal Salt} + H_2 \uparrow}$$ $$Zn + 2HCl \to ZnCl_2 + H_2 \uparrow$$

*(The evolved $H_2$ gas burns with a characteristic pop sound when tested with a burning splint!)*.

3. The Metal Reactivity Series

Reactivity Series

The Reactivity Series is an arrangement of metals in the vertical order of their decreasing chemical reactivity:

$$\mathbf{K > Na > Ca > Mg > Al > Zn > Fe > Pb > [H] > Cu > Hg > Ag > Au}$$
  • Top Metals ($K, Na, Ca$): Extremely reactive; stored under kerosene oil ($Na, K$) to prevent violent reaction with air moisture. Never found free in nature.
  • Middle Metals ($Zn, Fe, Pb$): Moderate reactivity; extracted by carbon reduction from oxides.
  • Bottom Noble Metals ($Cu, Ag, Au$): Unreactive; found in native free metallic state in river gravels and rocks.
  • Displacement Rule: A more reactive metal displaces a less reactive metal from its aqueous salt solution: $$Fe + CuSO_4(aq) \text{ [Blue]} \to FeSO_4(aq) \text{ [Pale Green]} + Cu \downarrow \text{ [Reddish-Brown Deposited]}$$

4. Alloys: Compositions & Engineering Utilities

Alloys

An Alloy is a homogeneous mixture of two or more metals, or a metal and a non-metal, fused together in a molten state.

Why Make Alloys? Pure metals are often too soft, chemically reactive, or prone to corrosion. Alloying increases hardness and tensile strength, lowers melting point, and prevents rusting!

Alloy Composition Special Properties Practical Uses
Brass Copper ($60-80\%$), Zinc ($20-40\%$) Lustrous golden look, malleable, resists corrosion Utensils, musical instruments, decorative hardware
Bronze Copper ($80-90\%$), Tin ($10-20\%$) Hard, highly sonorous, extremely corrosion resistant Medals, statues, ship propellers, bells
Stainless Steel Iron ($73\%$), Chromium ($18\%$), Nickel ($8\%$), Carbon ($1\%$) Does NOT rust in water, high tensile strength Cutlery, surgical scalpels, cooking cookware
Duralumin Aluminum ($95\%$), Copper ($4\%$), Magnesium ($0.5\%$), Manganese ($0.5\%$) Extremely light like aluminum, but strong as steel Aircraft bodies, pressure cookers, space vehicles

Key Formulas, Reactions & Definitions

Metal Acid Reaction
$$\text{Metal} + 2HCl \to \text{Metal Chloride} + H_2 \uparrow \quad (\text{Pop Sound Test})$$
Applies to metals above hydrogen in the reactivity series.
Reactivity Series Mnemonic Order
K > Na > Ca > Mg > Al > Zn > Fe > Pb > [H] > Cu > Hg > Ag > Au
Decreasing order of electropositive chemical reactivity.

Chemistry of Metals: Reactivity Hierarchy & Common Alloys

Metals & Non-Metals: Reactivity Series & Engineering Alloys THE METAL REACTIVITY SERIES K > Na > Ca > Mg Violent with cold water • Stored in Kerosene Al > Zn > Fe > Pb React with dilute acids → Release H2 ↑ (Pop sound!) [H] (Hydrogen Reference Standard) Cu > Hg > Ag > Au Unreactive noble metals • Native free state Displacement: Fe + CuSO4 → FeSO4 + Cu↓ FOUR ESSENTIAL ALLOYS 1. Brass: Cu (60-80%) + Zn (20-40%) Golden appearance • Hardware & musical instruments 2. Bronze: Cu (80-90%) + Sn (10-20%) Hard & sonorous • Statues, medals, bells 3. Stainless Steel: Fe + Cr + Ni + C 100% Rust-proof • Surgical scalpels, cutlery 4. Duralumin: Al (95%) + Cu + Mg + Mn Light as aluminum, strong as steel • Aircraft bodies • Exceptions: Mercury = Liquid metal • Bromine = Liquid non-metal METALS FORM BASIC OXIDES • NON-METALS FORM ACIDIC OXIDES • GRAPHITE CONDUCTS ELECTRICITY

Chapter Summary & 10 Key Takeaways

Takeaway 1
Metals are lustrous, malleable, ductile, sonorous conductors; non-metals are dull, brittle insulators.
Takeaway 2
Mercury (Hg) is the only liquid metal; Bromine (Br2) is the only liquid non-metal at room temperature.
Takeaway 3
Sodium and potassium are soft metals sliced with a knife; diamond is the hardest natural substance known.
Takeaway 4
Graphite is an exceptional non-metal allotrope that conducts electricity due to free delocalized electrons.
Takeaway 5
Metals react with oxygen to form basic oxides; non-metals react with oxygen to form acidic oxides.
Takeaway 6
Active metals (Na, K) react violently with cold water, evolving hydrogen and requiring storage under kerosene.
Takeaway 7
Metals above hydrogen displace hydrogen gas from dilute acids ($Zn + 2HCl \to ZnCl_2 + H_2 \uparrow$).
Takeaway 8
The Reactivity Series arranges metals from most reactive ($K$) to least reactive noble metals ($Au$).
Takeaway 9
An alloy is a homogeneous solid mixture enhancing strength, hardness, and corrosion resistance.
Takeaway 10
Key alloys: Brass ($Cu+Zn$), Bronze ($Cu+Sn$), Stainless Steel ($Fe+Cr+Ni+C$), Duralumin ($Al$ aircraft alloy).

Check Your Understanding (Diagnostic Practice Questions)

Diagnostic questions testing core conceptual clarity. Answers are hidden initially — solve each problem first, then click to reveal the step-by-step verified solution.

1
State two exceptions for each of the following properties: (a) Metals are hard solids at room temperature, (b) Non-metals are non-conductors of electricity, (c) Non-metals are dull and non-lustrous.
Reveal Answer & Explanation
Answer:

• (a) Metals are hard solids:
1. Mercury ($Hg$): A liquid metal at room temperature.
2. Sodium ($Na$) and Potassium ($K$): Extremely soft metals that can be cut effortlessly with a knife.
• (b) Non-metals are non-conductors:
1. Graphite (Carbon allotrope): Has free delocalized electrons, making it an excellent conductor of electricity used in electrodes.
• (c) Non-metals are non-lustrous:
1. Iodine crystals: Exhibit a lustrous metallic sheen.
2. Diamond: Shows extraordinary brilliance and sparkle due to high optical dispersion.


Mercury is liquid, Na/K are soft; Graphite conducts electricity; Iodine and diamond are lustrous.
2
What happens when an iron nail is dipped into a blue copper sulfate solution ($CuSO_4$)? Write the balanced chemical equation and state the type of reaction.
Reveal Answer & Explanation
Answer:

• Observations:
1. The intense blue color of the copper sulfate solution gradually fades and transforms into a pale green solution of ferrous sulfate ($FeSO_4$).
2. A reddish-brown powdery coating of pure copper metal ($Cu$) deposits over the surface of the iron nail.
• Chemical Equation:

$$Fe(s) + CuSO_4(aq) \text{ [Blue]} \to FeSO_4(aq) \text{ [Pale Green]} + Cu(s) \downarrow \text{ [Reddish-Brown]}$$


• Type of Reaction: Single Displacement Reaction (Iron is more reactive than copper and displaces it from its salt solution).


Iron displaces copper: blue $CuSO_4$ turns pale green $FeSO_4$, and reddish-brown copper deposits on the nail.
3
Why are Sodium and Potassium always stored immersed under kerosene oil in chemistry laboratories?
Reveal Answer & Explanation
Answer:

• Sodium and Potassium are located at the very top of the Metal Reactivity Series and are extremely chemically reactive.
• When exposed to open air, they react vigorously with atmospheric oxygen and moisture at room temperature, releasing hydrogen gas and generating intense exothermic heat that causes the hydrogen to spontaneously ignite and explode!
• They do not react with or dissolve in kerosene oil, which acts as an airtight protective barrier preventing contact with oxygen and moisture.


They react violently and catch fire with moisture/oxygen in air, but are inert under kerosene oil.
4
What is an Alloy? State the composition and one primary use of: (a) Brass, (b) Stainless Steel, (c) Duralumin.
Reveal Answer & Explanation
Answer:

• Definition: An Alloy is a homogeneous solid mixture of two or more metals, or a metal and a non-metal, blended in a molten state to improve mechanical and chemical properties.
• (a) Brass: Composition: Copper ($60-80\%$) + Zinc ($20-40\%$). Use: Decorative door hardware, musical instruments, electrical fittings.
• (b) Stainless Steel: Composition: Iron ($73\%$) + Chromium ($18\%$) + Nickel ($8\%$) + Carbon ($1\%$). Use: Rust-proof surgical scalpels and cooking utensils.
• (c) Duralumin: Composition: Aluminum ($95\%$) + Copper ($4\%$) + Magnesium ($0.5\%$) + Manganese ($0.5\%$). Use: Aircraft bodies and space satellites due to its high strength-to-weight ratio.


Brass = Cu+Zn; Stainless Steel = Fe+Cr+Ni+C; Duralumin = Al+Cu+Mg+Mn (aircraft metal).
5
Explain why cooking utensils are made of metals like aluminum or copper, but their handles are made of Bakelite or wood.
Reveal Answer & Explanation
Answer:

• Pan Body: Made of metals like aluminum, copper, or stainless steel because metals are excellent conductors of heat, allowing heat from the stove to conduct rapidly and cook food uniformly.
• Handles: Made of wood or thermosetting plastics like Bakelite because these non-metallic materials are poor conductors (thermal insulators) of heat, protecting the cook's hands from severe burns.


Pan body uses metals for thermal conduction; handles use wood/plastic for thermal insulation.
6
How do metallic oxides differ from non-metallic oxides in their chemical nature? Give one reaction for each with water.
Reveal Answer & Explanation
Answer:

• Metallic Oxides are BASIC: They react with water to form alkalis (bases) that turn red litmus paper blue:

$$MgO + H_2O \to Mg(OH)_2 \quad (\text{Magnesium hydroxide, basic})$$


• Non-Metallic Oxides are ACIDIC: They react with water to form acids that turn blue litmus paper red:

$$SO_2 + H_2O \to H_2SO_3 \quad (\text{Sulfurous acid, acidic})$$

.


Metal oxides are basic ($MgO + H_2O \to Mg(OH)_2$); non-metal oxides are acidic ($SO_2 + H_2O \to H_2SO_3$).
7
What happens when zinc granules are treated with dilute hydrochloric acid? Write the balanced chemical equation and describe the test for the gas evolved.
Reveal Answer & Explanation
Answer:

• Reaction: Zinc reacts vigorously with dilute hydrochloric acid to form zinc chloride and bubbles of colorless, odorless Hydrogen gas ($H_2$):

$$Zn(s) + 2HCl(aq) \to ZnCl_2(aq) + H_2(g) \uparrow$$


• Test for Hydrogen Gas: Bring a burning wooden splint near the mouth of the test tube. The gas ignites with a characteristic "POP" sound and burns with a pale blue flame, confirming it is Hydrogen.


$Zn + 2HCl \to ZnCl_2 + H_2 \uparrow$. Hydrogen gas burns with a characteristic "pop" sound.
8
Why is gold used for making jewelry, while iron is never used for that purpose?
Reveal Answer & Explanation
Answer:

• Gold ($Au$): Lies at the very bottom of the Reactivity Series (a noble metal). It is completely unreactive and does not tarnish, corrode, or react with air, water, or sweat, maintaining its brilliant golden luster for thousands of years. It is also highly malleable and ductile.
• Iron ($Fe$): Moderately reactive. In the presence of moist air, it readily oxidizes to form unsightly, flaky reddish-brown rust ($2Fe_2O_3 \cdot xH_2O$), deteriorating quickly.


Gold is a noble metal that never tarnishes or rusts; iron oxidizes quickly into flaky brown rust.
Finished Studying This Chapter?
READY TO PRACTICE?

Timed CBT Practice Tests (Exam Simulator)

Put your concepts to the test with official curriculum-aligned Foundation and Advanced practice tests. Get instant accuracy scores, time metrics, and step-by-step verified explanations.

Foundation Test
15 MCQs • Core Concepts
Advanced Test
15 MCQs • HOTS & Traps

All Class 7 Science Chapters

AI Study Friend

Instant Concept Tutor

Have a doubt in Metals and Non-Metals? Ask our AI study tutor for rapid explanations or customized quizzes.