Welcome to Bodhiclasses – your trusted learning partner on the journey to clarity, confidence, and concept mastery. Today, we bring you a special set of extra questions and answers for Class 7 Science Chapter 4 – The World of Metals and Non-Metals. These questions are designed to boost your understanding, improve exam performance, and encourage deeper thinking.
The World of Metals and Non-Metals: : Extra Questions NCERT Class 7 Science New
Multiple Choice Questions (MCQs)
- Which of the following is the most ductile metal?
(a) Iron (b) Silver (c) Gold (d) Zinc
Answer: (c) Gold - Which of the following is a good conductor of electricity?
(a) Wood (b) Rubber (c) Copper (d) Plastic
Answer: (c) Copper - Which of the following is a non-metal?
(a) Magnesium (b) Zinc (c) Sulfur (d) Aluminium
Answer: (c) Sulfur - Which non-metal is used in antiseptic solutions?
(a) Nitrogen (b) Oxygen (c) Chlorine (d) Iodine
Answer: (d) Iodine - Which metal is known for its high malleability?
(a) Gold (b) Iron (c) Zinc (d) Sodium
Answer: (a) Gold - Which of these metals is stored in kerosene due to high reactivity?
(a) Calcium (b) Iron (c) Sodium (d) Copper
Answer: (c) Sodium - Which of these is not a characteristic property of metals?
(a) Ductility (b) Brittleness (c) Malleability (d) Conductivity
Answer: (b) Brittleness - Which metal does not rust?
(a) Aluminium (b) Silver (c) Gold (d) Iron
Answer: (c) Gold - Which of these is a basic oxide?
(a) Sulfur dioxide (b) Carbon dioxide (c) Magnesium oxide (d) Phosphorus pentoxide
Answer: (c) Magnesium oxide - What is the nature of the oxide formed by non-metals?
(a) Neutral (b) Basic (c) Acidic (d) Alkaline
Answer: (c) Acidic
One-Mark Questions
- What is meant by lustre?
Answer: The shiny appearance of metals is called lustre. - Name one metal that is liquid at room temperature.
Answer: Mercury - Which non-metal supports combustion?
Answer: Oxygen - Give an example of a sonorous metal.
Answer: Iron - Name a non-metal that is essential for plant growth.
Answer: Nitrogen - What is corrosion?
Answer: The gradual destruction of metals due to environmental factors is called corrosion. - Name one use of aluminium foil.
Answer: It is used for food packaging. - Which non-metal is used for water purification?
Answer: Chlorine - What is the property of being drawn into wires called?
Answer: Ductility - Which metal is most malleable?
Answer: Gold
The World of Metals and Non-Metals
Two-Mark Questions
- What happens when a metal reacts with oxygen?
Answer: It forms a metal oxide, which is usually basic in nature. - Why is iron not suitable for jewellery?
Answer: Iron rusts easily and lacks the aesthetic appeal and shine of gold or silver. - Why is copper used in electrical wiring?
Answer: Copper is a good conductor of electricity and is ductile. - Explain sonority with an example.
Answer: The ability of metals to produce a ringing sound when struck. Example: School bell made of iron. - Why is rusting considered a problem?
Answer: It weakens iron structures and leads to economic loss due to frequent replacements. - How does magnesium oxide affect litmus paper?
Answer: It turns red litmus blue, indicating basic nature. - What is the role of zinc in preventing rusting?
Answer: Zinc coating (galvanisation) prevents iron from coming in contact with air and moisture. - Mention two uses of non-metals in daily life.
Answer: Oxygen for breathing, Iodine as antiseptic. - Differentiate between malleability and ductility.
Answer: Malleability: beaten into sheets; Ductility: drawn into wires. - Why are cooking vessels made of metals but their handles made of wood/plastic?
Answer: Metals conduct heat; handles are made of poor conductors for safety.
Higher Order Thinking Skills (HOTS) Questions: The World of Metals and Non-Metals
- Why do you think ancient Indian metallurgists preferred gold over iron for ornaments even though iron is stronger?
Answer: Gold does not rust, is more malleable and has aesthetic value, making it more suitable for ornaments. - Sodium is stored in kerosene but magnesium is not. Why?
Answer: Sodium reacts violently with air and water; magnesium is less reactive, so it doesn’t need kerosene storage. - If both iron and copper are metals, why does only iron rust in moist air?
Answer: Iron reacts with both oxygen and water to form rust. Copper forms a protective green patina that prevents further corrosion. - Can we use a wooden spoon for cooking instead of metal? Why or why not?
Answer: No, because wood is a poor conductor of heat and may burn or not heat food efficiently. - If sulfur does not react with water, can it still cause harm to the environment? Justify.
Answer: Yes, when burned it forms sulfur dioxide, a harmful gas that causes acid rain and respiratory issues.
