SAQ for Chapter 4 The World of Metals and Non-metals Class 7 Science NCERT
Important Questions1
Q1: What is malleability?
Answer
Malleability is the property of materials by which they can be beaten or hammered into thin sheets. Metals like copper, aluminium, and iron possess malleability.
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2
Q2: What happens when metals like copper and aluminium are beaten with a hammer?
Answer
Metals like copper and aluminium become flattened when beaten with a hammer, demonstrating their malleability.
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3
Q3: What is ductility?
Answer
Ductility is the property of materials that allows them to be drawn into wires. Metals such as gold and copper are highly ductile.
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4
Q4: What is sonority in metals?
Answer
Sonority is the property of metals to produce a ringing sound when struck. Metals like iron and steel are sonorous.
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5
Q5: Why are metals used for cooking utensils?
Answer
Metals are good conductors of heat, which makes them ideal for cooking utensils as they quickly transfer heat to food.
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6
Q6: What is corrosion?
Answer
Corrosion is the gradual deterioration of metals due to reactions with air, water, or other substances. For example, iron rusts when exposed to moist air.
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7
Q7: What happens when metals react with oxygen?
Answer
When metals react with oxygen, they form metal oxides, which are usually basic in nature.
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8
Q8: Why are metals like iron and copper used in electrical wiring?
Answer
Metals like iron and copper are good conductors of electricity, making them ideal for use in electrical wiring.
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9
Q9: Why is sodium stored in kerosene?
Answer
Sodium reacts vigorously with water and oxygen, generating a lot of heat. Storing sodium in kerosene prevents it from reacting with moisture and air.
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10
Q10: What is the importance of metals and non-metals in everyday life?
Answer
Metals and non-metals play vital roles in daily life. Metals are used in construction, electrical devices, and tools, while non-metals like oxygen and nitrogen are essential for life and plant growth.
SAQ