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Class 7 → Science → Chapter 4: The World of Metals and Non-metals
I. Chapter Summary:
This chapter introduces students to metals and non-metals, their properties, and uses. It explains how these materials differ in physical and chemical properties and how they are used in everyday life. Students also learn about basic reactions of metals and non-metals, their importance in industry, and safety precautions while handling them.
II. Key Concepts Covered:
- Metals:
Substances that are generally hard, shiny, and good conductors of heat and electricity (e.g., iron, copper, aluminium). - Non-metals:
Substances that are generally dull, brittle, and poor conductors (e.g., sulphur, oxygen, carbon). - Physical Properties of Metals:
- Lustrous (shiny)
- Malleable (can be hammered)
- Ductile (can be drawn into wires)
- Good conductors
- Physical Properties of Non-metals:
- Dull appearance
- Brittle
- Poor conductors
- Chemical Properties:
- Metals react with oxygen to form oxides
- Non-metals also react with oxygen
- Uses of Metals:
- Construction (iron, steel)
- Electrical wiring (copper)
- Utensils (aluminium)
- Uses of Non-metals:
- Oxygen for respiration
- Carbon in fuels
- Sulphur in medicines
- Safety Measures:
- Handle chemicals carefully
- Avoid direct contact with reactive metals
III. Important Questions:
(A) MCQs (1 Mark):
- Metals are generally:
(a) Dull
(b) Shiny ✅
(c) Soft
(d) Liquid - Non-metals are:
(a) Conductors
(b) Insulators ✅
(c) Metals
(d) Liquids - Copper is used for:
(a) Cooking
(b) Wiring ✅
(c) Fuel
(d) Medicine - Sulphur is a:
(a) Metal
(b) Non-metal ✅
(c) Alloy
(d) Liquid
IV. Key Formulas/Concepts:
Basic chemical concept:
Metal+Oxygen→Metal Oxidetext{Metal} + text{Oxygen} rightarrow text{Metal Oxide}Metal+Oxygen→Metal Oxide
- Metals → Good conductors, malleable, ductile
- Non-metals → Poor conductors, brittle
- Chemical reaction → Formation of oxides
(B) Short Answer Questions (2/3 Marks):
- What are metals and non-metals?
- List physical properties of metals.
- How do non-metals differ from metals?
- Give examples of uses of metals.
(C) Long Answer Questions (5 Marks):
- Explain properties of metals with examples.
- Describe properties of non-metals.
- Compare metals and non-metals.
- Explain uses of metals and non-metals in daily life.
(D) HOTS Questions:
- Why are metals used for making electrical wires?
- Why are non-metals generally poor conductors of electricity?
V. Deleted Portions (CBSE 2025–2026):
No portions have been deleted from this chapter as per the rationalized NCERT textbooks.
VI. Chapter-Wise Marks Bifurcation (Estimated – CBSE 2025–2026):
| Unit/Chapter | Estimated Marks | Type of Questions Typically Asked |
|---|---|---|
| The World of Metals and Non-metals | 6–8 Marks | MCQs, Short Answers, Case-based, Diagram-based |
Note: This is an estimate. Actual marks distribution may vary.
VII. Previous Year Questions (PYQs):
1 Mark:
- What is a metal? (CBSE 2020)
2/3 Marks:
- List properties of metals. (CBSE 2019)
- What are non-metals? (CBSE 2021)
5 Marks:
- Compare metals and non-metals. (CBSE 2022)
- Explain uses of metals. (CBSE 2023)
VIII. Real-World Application Examples:
- Iron is used in construction of buildings and bridges.
- Copper wires are used in electrical circuits.
- Oxygen is essential for breathing.
- Carbon is used as fuel in coal and petroleum.
IX. Student Tips & Strategies for Success:
Time Management:
- Study properties and uses separately.
Exam Preparation:
- Focus on differences between metals and non-metals.
- Learn examples clearly.
Stress Management:
- Use charts for comparison.
- Revise regularly.
X. Career Guidance & Exploration:
- Science Stream: Metallurgy, Chemical Engineering
- Commerce Stream: Industrial Management
- Arts Stream: Environmental Studies
Entrance Exams:
- JEE (Engineering)
- NEET (Medical)
- Polytechnic exams
XI. Important Notes:
- Focus on properties and examples.
- Practice comparison questions.
- Understand uses in daily life.
- Refer NCERT textbook for accuracy.