Class 7 Science - TAMILNADU
The World of Metals and Non-metals
The chapter 'The World of Metals and Non-metals' in Class 7 Science introduces students to the fascinating classification of elements based on their physical and chemical properties. Students will learn how to distinguish between metals like iron, copper, and aluminum, and non-metals like carbon, sulfur, and oxygen. The chapter covers important characteristics such as malleability, ductility, electrical and thermal conductivity, and sonority. Understanding these properties is crucial as it forms the foundation for studying chemical reactions in higher classes. This chapter carries significant weight in Tamil Nadu Samacheer Kalvi board exams through objective and descriptive questions.
Start Learning FreeKey Concepts
Physical Properties of Metals
Metals are generally hard, lustrous (shiny), malleable, ductile, good conductors of heat and electricity, and sonorous.
Physical Properties of Non-metals
Non-metals are soft, non-lustrous, brittle, poor conductors of heat and electricity, and non-sonorous.
Malleability and Ductility
Malleability is the property of metals to be beaten into thin sheets, while ductility is the ability to be drawn into wires.
Conduction of Heat and Electricity
Metals allow heat and electricity to pass through them easily, whereas non-metals (except graphite) do not.
Uses of Metals and Non-metals
Metals are used in making machinery, utensils, and wires, while non-metals are essential for life (oxygen), breathing, and fertilizers.
Important Formulas
Board Exam Info
In the Tamil Nadu (Samacheer Kalvi) Class 7 Science exams, this chapter typically carries around 6 to 8 marks. Questions frequently appear as fill-in-the-blanks, matching the following, give reasons (e.g., why wires are made of copper), and short-answer questions differentiating metals and non-metals.
Frequently Asked Questions
Why are copper and aluminum used for making electrical wires?
Copper and aluminum are used because they are excellent conductors of electricity and are ductile enough to be drawn into thin wires.
Are all metals solid at room temperature?
No, most metals are solid, but mercury is a unique metal that remains in a liquid state at room temperature.
Why is sodium stored in kerosene?
Sodium is an extremely reactive metal that catches fire when it comes into contact with air and moisture, so it is stored in kerosene to prevent accidents.
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