This MCQ module is based on: Metals and Non-metals
TOPIC 14 OF 46
Metals and Non-metals
🎓 Class 7
Science
CBSE
Theory
Ch 4 — The World of Metals and Non-metals
⏱ ~8 min
🌐 Language: [gtranslate]
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Summary — At a Glance
Here is a side-by-side comparison of everything we learnt in Chapter 4 about metals and non-metals.
| Property | Metals | Non-metals |
|---|---|---|
| Lustre | Shiny (iron, Cu, Al) | Dull (coal, sulphur) |
| Malleability | Can be beaten into sheets (Au, Ag) | Break into powder (brittle) |
| Ductility | Drawn into wires (Cu, Fe) | Cannot be drawn |
| Sonorousness | Produce a ringing sound | Dull thud |
| Heat/Electricity conductor | Good (Cu, Al) | Poor (except graphite) |
| State at room temperature | Mostly solid; exception: mercury (liquid) | Solids, liquids (Br) & gases (O2, N2) |
| Density & hardness | Mostly high & hard; exceptions: Na, K soft | Mostly low density; brittle |
| Reaction with O2 | Form basic oxides (MgO, CuO) | Form acidic oxides (CO2, SO2) |
| Reaction with water | Some do (Na vigorously; Fe with steam); Cu, Ag, Au do not | Generally no reaction |
| Reaction with dilute acid | Release H2 gas (pop test) | Do not release H2 |
| Reaction with base | A few (Al, Zn) release H2 | No simple reaction |
| Uses | Construction, wiring, coins, jewellery, tools | Breathing, fertilisers, fuels, pencils, antiseptics |
Keywords
LustreShiny appearance of metals.
MalleabilityCan be hammered into sheets.
DuctilityCan be drawn into wires.
SonorousProduces a ringing sound.
ConductorAllows heat/electricity to flow.
BrittleBreaks into pieces when hit.
Basic oxideMetal oxide — turns red litmus blue.
Acidic oxideNon-metal oxide — turns blue litmus red.
Pop testBurning splint test for H2 gas.
Reactivity seriesOrder of metals by reactivity.
RustReddish-brown Fe2O3·nH2O on iron.
GalvanisationCoating iron with zinc.
AlloyMixture of metals (e.g. stainless steel).
GraphiteA non-metal that conducts electricity.
NCERT Exercises — with Solutions
Try each question first; click Show Solution only after your own attempt.
1Which metal is commonly used for packaging food as a thin sheet?
Aluminium. It is highly malleable, non-toxic, resists corrosion and is light. Aluminium foil is used to wrap chocolates, medicines and lunch in tiffins.
2Which of the following metals survive without rusting in contact with water? (a) Iron (b) Copper (c) Gold (d) Silver
Copper, Gold and Silver do not rust in contact with water because they lie very low in the reactivity series. Iron rusts readily. (Gold is the most inert — that is why it stays shining for centuries.)
3State whether true or false, giving a reason:
(a) All metals are solid at room temperature.
(b) Non-metal oxides are basic in nature.
(c) Copper reacts with dilute HCl to release hydrogen gas.
(a) All metals are solid at room temperature.
(b) Non-metal oxides are basic in nature.
(c) Copper reacts with dilute HCl to release hydrogen gas.
(a) False — mercury is a liquid metal at room temperature.
(b) False — non-metal oxides are acidic (e.g., CO2, SO2). Only metal oxides are basic.
(c) False — copper is below hydrogen in the reactivity series, so it does not displace hydrogen from dilute HCl.
(b) False — non-metal oxides are acidic (e.g., CO2, SO2). Only metal oxides are basic.
(c) False — copper is below hydrogen in the reactivity series, so it does not displace hydrogen from dilute HCl.
4Why are only a few metals used in making jewellery?
Jewellery needs metals that:
(i) have a beautiful lustre that stays even after years of use,
(ii) are malleable and ductile so they can be shaped into fine designs,
(iii) do not react with air, sweat or water (no tarnishing or rusting).
Only gold, silver and platinum meet all three — that is why they dominate the jewellery market.
(i) have a beautiful lustre that stays even after years of use,
(ii) are malleable and ductile so they can be shaped into fine designs,
(iii) do not react with air, sweat or water (no tarnishing or rusting).
Only gold, silver and platinum meet all three — that is why they dominate the jewellery market.
5Match the use in Column I with the metal/non-metal in Column II.
| Column I (Use) | Column II |
|---|---|
| (i) Thermometer | (p) Copper |
| (ii) Electrical wiring | (q) Graphite |
| (iii) Pencil lead | (r) Mercury |
| (iv) Galvanising iron | (s) Zinc |
| (v) Iodised salt | (t) Iodine |
(i)→(r), (ii)→(p), (iii)→(q), (iv)→(s), (v)→(t).
6What happens when oxygen reacts with magnesium and with sulphur? Write the equations and state one important difference between the products.
2 Mg + O2 → 2 MgO (white ash)
S + O2 → SO2 (colourless, pungent gas)
Difference: MgO is a metal oxide — when dissolved in water it forms a base (turns red litmus blue). SO2 is a non-metal oxide — it forms an acid in water (turns blue litmus red).
S + O2 → SO2 (colourless, pungent gas)
7Name three metals that react with water and three that do not.
React with water: Sodium (Na), Potassium (K) and Calcium (Ca) — react with cold water releasing H2.
Do not react with water: Copper (Cu), Silver (Ag) and Gold (Au) — they lie very low in the reactivity series.
Do not react with water: Copper (Cu), Silver (Ag) and Gold (Au) — they lie very low in the reactivity series.
8Explain why galvanising iron prevents it from rusting.
Galvanisation means coating iron with a thin layer of zinc. Two things happen:
(i) The zinc layer acts as a physical barrier, keeping oxygen and moisture away from iron.
(ii) Even if the layer is scratched, zinc is more reactive than iron in the reactivity series — so zinc reacts with air first (sacrificial protection) and the iron underneath remains safe.
That is why galvanised buckets, gates and roofing sheets last many years without rusting.
(i) The zinc layer acts as a physical barrier, keeping oxygen and moisture away from iron.
(ii) Even if the layer is scratched, zinc is more reactive than iron in the reactivity series — so zinc reacts with air first (sacrificial protection) and the iron underneath remains safe.
That is why galvanised buckets, gates and roofing sheets last many years without rusting.
9Mercury is used in thermometers. Which properties of mercury make it suitable?
(i) Mercury is a liquid at room temperature — the only metal that is — so it flows inside a narrow tube.
(ii) It has a high, uniform rate of thermal expansion — it rises and falls smoothly with temperature.
(iii) It is shiny/opaque, so the silver thread is easy to read.
(iv) It does not stick to the glass walls of the thermometer.
(Note: Modern thermometers avoid mercury because it is toxic.)
(ii) It has a high, uniform rate of thermal expansion — it rises and falls smoothly with temperature.
(iii) It is shiny/opaque, so the silver thread is easy to read.
(iv) It does not stick to the glass walls of the thermometer.
(Note: Modern thermometers avoid mercury because it is toxic.)
10Seema's mother wears a gold ring every day while cooking, washing utensils and working in water. Even after many years, the ring still shines like new. Explain why.
Gold lies at the very bottom of the reactivity series. It does not react with:
• Oxygen in the air — so it does not tarnish.
• Water or moisture — so it does not rust.
• Dilute acids from food, sweat or detergents — so it is not attacked.
This chemical inertness, combined with gold's natural lustre and malleability, is why gold jewellery stays shining for generations.
• Oxygen in the air — so it does not tarnish.
• Water or moisture — so it does not rust.
• Dilute acids from food, sweat or detergents — so it is not attacked.
This chemical inertness, combined with gold's natural lustre and malleability, is why gold jewellery stays shining for generations.
Well done! You have completed Chapter 4 — The World of Metals and Non-metals. Next time you see an iron gate, a copper wire, a coin or a pencil, try to spot the metal or non-metal property that made it useful!
Frequently Asked Questions — Metals and Non-metals — Chapter 4 Exercises
What does the topic 'Metals and Non-metals — Chapter 4 Exercises' cover in Class 7 Science?
The topic 'Metals and Non-metals — Chapter 4 Exercises' 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, properties, uses, rusting, NCERT exercises, 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 'Metals and Non-metals — Chapter 4 Exercises' important for Class 7 NCERT Science?
'Metals and Non-metals — Chapter 4 Exercises' 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 Metals and Non-metals — Chapter 4 Exercises?
The key concepts in 'Metals and Non-metals — Chapter 4 Exercises' for Class 7 Science are: metals, non-metals, properties, uses, rusting, NCERT exercises. 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 Metals and Non-metals — Chapter 4 Exercises taught using activities in NCERT Curiosity Class 7?
NCERT Curiosity Class 7 Science teaches 'Metals and Non-metals — Chapter 4 Exercises' 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.
How should Class 7 students prepare for the Chapter 4 exercises?
To prepare for the Chapter 4 — The World of Metals and Non-metals — exercises in NCERT Class 7 Science, students should first revise the theory in Parts 1–3 and make a short list of definitions and diagrams for metals, non-metals, properties, uses, rusting, NCERT exercises. Next, attempt each exercise question on their own before checking the solution. Pay extra attention to MCQs, assertion–reason questions and short-answer items, as these appear in CBSE competency-based tests. Practising with the NCERT Curiosity textbook, the exemplar questions, and the MyAiSchool practice bank helps Class 7 students score better in unit tests and the annual examination.
How does 'Metals and Non-metals — Chapter 4 Exercises' connect to other chapters of Class 7 Science?
'Metals and Non-metals — Chapter 4 Exercises' 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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