This MCQ module is based on: Physical Properties of Metals and Non-metals
TOPIC 11 OF 46
Physical Properties of Metals and Non-metals
🎓 Class 7
Science
CBSE
Theory
Ch 4 — The World of Metals and Non-metals
⏱ ~14 min
🌐 Language: [gtranslate]
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[myaischool_lt_science_assessment grade_level="class_7" science_domain="chemistry" difficulty="basic"]
Meeting an Ironsmith in Rajasthan
During their summer holiday, Yashwant and Anandi visited their grandparents' village in Rajasthan. One afternoon, they walked past a busy open shed where the air rang with the sound of hammer on hot metal. This was the workshop of Sudarshan uncle, the village ironsmith. Glowing pieces of iron were being shaped into tools their neighbours would use for cooking and farming.
Sudarshan uncle proudly showed them what he makes every week — flat cooking pans called tawas, water baltis (buckets), kitchen tongs (chimtas), digging phawras (spades), kulhadis (axes), khurpis (trowels) and garden jelees (rakes). Every item was strong, shiny and ringing — all made from the same material: iron.
Wonder question: Why is almost every tool in Sudarshan uncle's shop made of metal and not wood, plastic or stone? What special properties do metals have that make them so useful?
4.1 Physical Properties of Metals
Scientists call the properties we can observe or measure without changing the substance its physical properties. Let us study the physical properties one by one and see how metals differ from non-metals.
(a) Lustre — the Shine
A freshly cut or polished metal surface has a lustre — a bright, reflective shine. Non-metals, on the other hand, usually look dull.
Activity 4.1 — Looking at Shine L2 Understand
Materials: small pieces of iron, aluminium, copper, zinc, coal, sulphur.
What to do: Rub each sample gently with sandpaper and observe its surface in sunlight. Sort them into two groups — "shiny" and "dull".
Predict: Which samples do you think will shine after rubbing?
Iron, aluminium, copper and zinc all develop a clear metallic shine — they are lustrous. Coal and sulphur stay dull and powdery — they are non-lustrous. So, metals generally show lustre while non-metals do not.
(b) Malleability
When a piece of metal is beaten with a hammer, it flattens into a thin sheet without breaking. This property is called malleability.
- Gold and silver are so malleable that they are beaten into foils (varak) used to decorate sweets like kaju katli.
- Aluminium foil used to pack lunches shows how easily the metal rolls into sheets.
- If you hammer coal or a lump of sulphur, it simply breaks into powder — non-metals are not malleable. They are called brittle.
(c) Ductility
Metals can also be drawn out into thin wires. This property is called ductility. The copper wire inside every electric cable and the thin iron wire used in fences are possible because copper and iron are ductile. Non-metals like sulphur and phosphorus break instantly if you try to stretch them.
(d) Sonorousness
Strike a steel plate or a metal bell with a stick — a clear ringing sound is produced. Metals are therefore said to be sonorous. That is why temple bells, school gongs, cymbals and musical triangles are all made of metals. A lump of coal struck with the same stick will give a dull thud — non-metals are not sonorous.
(e) Conductivity — Heat & Electricity
Hold a metal spoon in a hot cup of tea for a minute. The end of the spoon also starts to feel warm — heat has travelled through the metal. Metals are good conductors of heat. Similarly, the copper wires hidden behind your house walls carry electricity easily, because metals are also excellent conductors of electricity.
Most non-metals do not conduct electricity — that is why plastic and rubber are used to cover electric wires. But there is one famous exception: graphite (a form of carbon) is a non-metal, yet it conducts electricity. This is why graphite rods are used inside dry cells.
(f) Hardness
Most metals are hard — you cannot scratch iron, copper or zinc with your finger nail. But not every metal is tough. Sodium and potassium are so soft that they can be sliced with an ordinary knife just like butter!
(g) Density, State & Melting Point
- Density: Most metals are heavy for their size — they have a high density. (Exceptions: lithium, sodium, potassium, which float on water.)
- State at room temperature: Nearly all metals are solid. The famous exception is mercury, which is a silvery liquid at room temperature (used inside thermometers).
- Melting point: Metals usually melt only at very high temperatures (iron melts at about 1538 °C). But sodium melts at just 98 °C and gallium melts on your warm palm (about 30 °C)!
Key idea: Materials that are lustrous, malleable, ductile, sonorous and good conductors of heat and electricity are called metals. Materials that are dull, brittle, poor conductors and non-sonorous are called non-metals.
Interactive: Metal or Non-metal Property Tester
Click a property chip to place it under the correct column. If it belongs there, it turns green; otherwise it flashes red.
Shiny surface
Breaks into powder
Ductile (wires)
Dull appearance
Sonorous ring
Poor conductor
Malleable sheets
Brittle
Metal
Non-metal
Score: 0 / 8
Activity 4.2 — Test It Yourself L3 Apply
Collect these items from your home: an aluminium foil piece, a copper wire, a piece of wood, a pencil lead (graphite), a plastic comb and a steel spoon. With your teacher's help, build a simple cell-and-bulb circuit and test which items make the bulb glow.
Predict: Which three items will make the bulb glow?
Bulb glows with aluminium foil, copper wire, steel spoon and pencil lead (graphite). It does not glow with wood or plastic. Wood and plastic are non-metals that do not conduct electricity; graphite is the non-metal exception.
Competency-Based Questions L3 Apply
Meera visits a jewellery workshop. The craftsman takes a tiny bead of gold, places it on an iron plate and hammers it for almost an hour until it becomes a paper-thin sheet. He then cuts another strip and pulls it through tiny holes in a steel block to make a fine thread-like wire. Meera also sees small chunks of sulphur powder being weighed for an ointment.
1. The property that allows the gold bead to become a thin sheet is called:
(b) Malleability — the ability to be hammered into sheets.
2. Which property is used when gold is pulled through the tiny holes?
Ductility — stretching into a wire without breaking.
3. Why can the craftsman never hammer sulphur into a sheet like gold? L4
Sulphur is a non-metal and is brittle — its particles do not slide over one another when hammered. It crumbles into powder instead of spreading out.
4. State True or False: "All non-metals are poor conductors of electricity."
False. Graphite (a form of carbon) is a non-metal but conducts electricity.
5. Meera wonders why temple bells and school gongs are always made of metal. Justify in one sentence.
Because metals are sonorous — they produce a long, clear ringing sound when struck, unlike non-metals which give only a dull thud.
Assertion–Reason Questions
Choose: (A) Both A and R true, R explains A. (B) Both true, R does not explain A. (C) A true, R false. (D) A false, R true.
A: Copper wires are used for electrical wiring inside homes.
R: Copper is ductile and a very good conductor of electricity.
(A) — Both are correct, and ductility plus conductivity together explain why copper is chosen.
A: Mercury is kept in a sealed glass thermometer.
R: Mercury is the only metal that is liquid at room temperature.
(A) — Mercury's liquid state at room temperature lets it expand smoothly in the thermometer tube.
A: Sulphur cannot be drawn into a wire.
R: Sulphur is a non-metal and is brittle.
(A) — Brittleness of non-metals prevents them from being stretched into wires.
Frequently Asked Questions — Physical Properties of Metals and Non-metals
What does the topic 'Physical Properties of Metals and Non-metals' cover in Class 7 Science?
The topic 'Physical Properties of Metals and Non-metals' is part of NCERT Class 7 Science Chapter 4 — The World of Metals and Non-metals. It covers the key ideas of metals, non-metals, lustre, malleability, ductility, conductivity, hardness, sonority, explained through everyday examples, labelled diagrams and hands-on activities drawn from the NCERT Curiosity textbook. Students learn not just definitions but also the reasoning behind each concept so they can answer competency-based questions and assertion–reason items. The lesson helps Class 7 students build a strong base for higher classes by linking each idea to real observations at home, school and in nature, and by preparing them for CBSE school assessments and Olympiads.
Why is 'Physical Properties of Metals and Non-metals' important for Class 7 NCERT Science?
'Physical Properties of Metals and Non-metals' is important because it builds core scientific thinking that Class 7 students will use throughout middle and secondary school. NCERT Chapter 4 — The World of Metals and Non-metals — introduces metals and related ideas that appear again in Class 8, 9 and 10 Science. Mastering this subtopic helps students read labels and safety signs, understand news about science and technology, and perform better in CBSE school exams. The chapter also encourages curiosity and evidence-based thinking — skills that support the National Education Policy (NEP) 2020 focus on conceptual understanding and competency-based learning.
What are the key concepts students should remember from Physical Properties of Metals and Non-metals?
The key concepts in 'Physical Properties of Metals and Non-metals' for Class 7 Science are: metals, non-metals, lustre, malleability, ductility, conductivity, hardness, sonority. Students should be able to define each term in their own words, give at least one everyday example, and explain how the concept connects to other chapters in NCERT Class 7 Science. For example, linking the idea to daily life — in the kitchen, classroom or outdoors — makes revision easier. Writing short notes, drawing labelled diagrams and solving the NCERT in-text and exercise questions for Chapter 4 will help students retain these concepts for unit tests and the annual CBSE examination.
How is Physical Properties of Metals and Non-metals taught using activities in NCERT Curiosity Class 7?
NCERT Curiosity Class 7 Science teaches 'Physical Properties of Metals and Non-metals' using an inquiry-based approach with Predict–Observe–Explain activities. Students are asked to make a guess first, then perform a simple experiment with safe, easily available materials, and finally explain what they observed. This matches the NEP 2020 focus on learning by doing. For Chapter 4 — The World of Metals and Non-metals — the textbook includes hands-on tasks, labelled diagrams and questions that build Bloom's Taxonomy skills from Remember (L1) to Create (L6). Teachers use these activities, along with competency-based questions (CBQs) and assertion–reason items, to check real understanding rather than rote memorisation.
What real-life examples of metals can Class 7 students observe at home?
Class 7 students can observe metals at home in many simple ways linked to 'Physical Properties of Metals and Non-metals'. Kitchens, school bags, playgrounds and the night sky are full of examples that connect to NCERT Chapter 4 — The World of Metals and Non-metals. For instance, students can check labels on food and cleaning products, watch changes while cooking, or observe the Sun and Moon across a week. Keeping a small science diary — noting the date, what was observed and a quick sketch — turns everyday life into a science lab. These real-life connections make concepts stick and prepare students well for competency-based questions in CBSE Class 7 Science.
How does 'Physical Properties of Metals and Non-metals' connect to other chapters of Class 7 Science?
'Physical Properties of Metals and Non-metals' connects to many other chapters in NCERT Class 7 Science Curiosity. The ideas of metals appear again when students study related topics like heat, light, changes, life processes and Earth-Sun-Moon. For example, understanding this subtopic helps in building mental models for later chapters and for Class 8, 9 and 10 Science. Teachers often use cross-chapter questions in CBSE examinations to test whether students can apply what they learned in Chapter 4 — The World of Metals and Non-metals — to new situations. This integrated approach matches the NEP 2020 and NCF 2023 focus on holistic, competency-based learning.
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