Class 7 Science - TELANGANA
The World of Metals and Non-metals
The chapter 'The World of Metals and Non-metals' in Class 7 Science introduces Telangana students to the fascinating classification of elements based on their physical and chemical properties. Students learn to distinguish between shiny, malleable metals like iron and copper, and brittle, non-lustrous non-metals like carbon and sulfur. The chapter covers essential concepts such as conductivity, malleability, ductility, and the reactions of metals and non-metals with oxygen and water. This foundational chapter is crucial for board exam preparation as it builds the basis for advanced chemistry topics in higher classes and frequently features in both objective and descriptive questions.
Start Learning FreeKey Concepts
Physical Properties of Metals
Metals are generally hard, lustrous (shiny), malleable (can be beaten into sheets), ductile (can be drawn into wires), and are good conductors of heat and electricity.
Physical Properties of Non-metals
Non-metals are mostly soft, dull in appearance, brittle (break easily when hammered), poor conductors of heat and electricity, and exist in solid, liquid, or gaseous states.
Malleability and Ductility
Malleability is the property that allows metals to be beaten into thin sheets, while ductility is the ability to stretch metals into thin wires.
Conduction of Heat and Electricity
Metals allow heat and electricity to pass through them easily due to free electrons, making them ideal for cooking utensils and electrical wires, unlike non-metals.
Reaction with Oxygen
When metals react with oxygen, they form basic oxides (e.g., magnesium oxide), whereas non-metals react with oxygen to form acidic or neutral oxides.
Important Formulas
Board Exam Info
In the Telangana (TSBSE) Class 7 Science examinations, this chapter typically carries around 6 to 8 marks. Questions usually include fill-in-the-blanks, matching types, differentiating properties between metals and non-metals, and short answer questions explaining why certain materials are used for specific household or electrical items.
Frequently Asked Questions
Why are electric wires made of copper or aluminium?
Copper and aluminium are metals, which means they are very good conductors of electricity and are ductile enough to be drawn into thin wires.
Is graphite a metal or a non-metal?
Graphite is a form of carbon, which is a non-metal. However, it is an exception because it is a good conductor of electricity.
What happens when magnesium ribbon burns in air?
Magnesium reacts with oxygen in the air to form a white powdery ash called magnesium oxide, which is basic in nature.
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