The67Sprint — LearningMap: The World of Metals and Non-metals

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✨ Physical Properties

Metals are hard, lustrous, sonorous, and good conductors of heat and electricity
Non-metals are dull, brittle, non-sonorous, and poor conductors (insulators)
Malleability: can be hammered into thin sheets — e.g. aluminium foil
Ductility: can be drawn into thin wires — e.g. copper wire
1 gram of gold can be stretched into a wire 2 kilometres long

🔄 Reaction with Oxygen

Metals + Oxygen → Basic Oxides — magnesium burns to form MgO, turns red litmus blue
Non-metals + Oxygen → Acidic Oxides — sulfur burns to form SO₂, turns blue litmus red
MgO dissolves in water to form magnesium hydroxide, Mg(OH)₂ — the base
SO₂ dissolves in water to form sulfurous acid, H₂SO₃ — this is what turns litmus red

M→Blue (Basic) N→Red (Acidic)

⚗️ Reaction with Acids

Metal + Dilute Acid → Salt + Hydrogen gas
Hydrogen gas is identified by a characteristic "pop" sound near a flame
Non-metals generally do not react with dilute acids

🚨 Rule Breakers & Storage

Sodium and potassium are so soft they can be cut with a knife
Mercury is the only metal that is liquid at room temperature
Graphite (a non-metal) conducts electricity; iodine (a non-metal) is lustrous
Sodium is stored in kerosene — it reacts violently with air and water
Phosphorus is stored in water — it catches fire in air but ignores water

Memory Cheat Code

Metals Make it Blue (Basic), Non-metals turn litmus Red (Acidic) — the fastest way to lock in oxide behaviour before an exam.

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C7_Sci_Ch4_LearningMap_WorldOfMetalsAndNonMetals Hero

Sprint Facts — Metals & Non-metals

Rusting Needs Both Oxygen AND water together — never just one alone

Uses of Non-metals Oxygen (breathing), Nitrogen (fertilizers), Chlorine (water purification), Iodine (antiseptic)

Galvanisation Zinc coating protects iron — durable and flexible, unlike brittle sulfur

Gold & Silver Most malleable and ductile of all metals — 1g gold stretches 2km

Iron Pillar of Delhi Over 1,600 years old, rust-free due to high-phosphorus iron and ancient forging

"Pop" Test Hydrogen gas from metal + acid reactions burns with a distinct pop sound

🔑 Key Terms

Malleability

The property allowing a material to be hammered into thin sheets without breaking

Ductility

The ability of a material to be drawn or stretched into thin wires

Corrosion

The gradual degradation of a metal's surface through reaction with its environment

Galvanisation

Protecting iron from rusting by coating it with a thin layer of zinc

Sonority

The property of producing a clear, ringing sound when struck — unique to metals

Basic & Acidic Oxides

Metal oxides turn red litmus blue (basic); non-metal oxides turn blue litmus red (acidic)

🏆 Olympiad & Challenger Edge

The Iron Pillar's Secret

High-phosphorus, low-sulfur iron combined with intense ancient forging created Misawite — a thin passive layer that has blocked oxygen and moisture from the Delhi pillar for over 1,600 years.

A Journey Through History

The pillar was originally erected by King Chandragupta II of the Gupta Empire in present-day Madhya Pradesh, and was later moved to Delhi by the Tomar King Anangpal II.

Why Not Sulfur-Coat Iron?

Sulfur ignores water but is brittle — it cracks and shatters like glass, letting air and moisture back in. Zinc, being a metal, forms a flexible, durable protective barrier instead.

The Three Test-Tube Proof

Boiled water sealed with oil removes dissolved oxygen; anhydrous calcium chloride absorbs all moisture. Only a nail in plain tap water — with both air and water present — actually rusts.

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Malleable & Conductive?

A material that flattens under a hammer and lights a bulb when wired to a battery proves both malleability and electrical conductivity — a metal.

The Rusting Test Tubes

Boiled water + oil removes oxygen. Anhydrous CaCl₂ absorbs moisture. Only the nail in tap water — with both present — rusts.

Sodium's Assertion-Reason

Sodium is stored in kerosene because it reacts violently with cold water, producing hydrogen gas that instantly ignites.

Smart Cookware

Copper and aluminium pans conduct heat into food; plastic or wooden handles insulate so hands don't burn.

Charging Cables

Ductile copper carries current fast inside the cable; a rubbery non-metal coating outside prevents shocks.

Clean Drinking Water

Chlorine, a non-metal, is added to purify swimming pools and drinking water supplies by killing bacteria.

The Rusting Trap

"Air OR water causes rust" loses marks. Rusting strictly needs BOTH oxygen and moisture present at the same time.

Basic vs. Acidic Oxides

Don't mix them up — metal oxides are basic (turn red litmus blue); non-metal oxides are acidic (turn blue litmus red).

Not Every Rule Holds

Graphite conducts electricity, iodine is lustrous, mercury is liquid, sodium is soft — always check for exceptions.

Logic Chain

Step 1

An iron surface is exposed to both atmospheric oxygen and moisture in the air or rain

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Step 2

Oxygen and water react with the iron together, triggering an electrochemical reaction on the surface

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Step 3

A reddish-brown, flaky compound called rust forms and gradually eats into the metal

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Step 4

Painting, oiling, or galvanising with zinc seals out air and moisture to stop the process

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Mentor Byte

"When a rusting question gives you three test tubes, name every condition precisely: boiled water plus oil removes dissolved oxygen, anhydrous calcium chloride absorbs moisture, and only the tube with both air and water present will actually rust. Examiners award marks for stating both conditions together — never just one."

💛 Parent Tip

Point out a rusty gate or railing near home and ask your child to explain, using both words "oxygen" and "water," exactly why it rusted. If they can name both causes together, the concept has truly stuck.