Class 7 Science - GUJARAT
The World of Metals and Non-metals
In the chapter 'The World of Metals and Non-metals', Class 7 GSEB students explore the fascinating physical and chemical properties that divide solid elements into two main groups. Students learn why metals like iron and copper are shiny, malleable, and conduct electricity, while non-metals like carbon and sulfur are brittle and dull. The chapter covers key concepts such as malleability, ductility, conduction of heat and electricity, and how metals react with oxygen and water to form oxides. Understanding these properties is crucial for board exams as it forms the foundation for chemistry in higher classes and explains everyday material uses.
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, dull in appearance, non-malleable, brittle, and poor conductors of heat and electricity.
Malleability and Ductility
Malleability is the property by which metals can be beaten into thin sheets, while ductility is the ability to be drawn into wires.
Reaction with Oxygen
Metals react with oxygen to form basic oxides, whereas non-metals react with oxygen to form acidic or neutral oxides.
Displacement Reactions
A more reactive metal can displace a less reactive metal from its salt solution in water.
Important Formulas
Board Exam Info
This chapter typically carries around 6 to 8 marks in the Gujarat (GSEB) Science examinations. Common question types include fill in the blanks, true or false, differentiating between physical and chemical properties of metals and non-metals, giving reasons for specific uses (like electrical wires made of copper), and short descriptive answers on displacement reactions.
Frequently Asked Questions
Why are electrical wires made of copper or aluminium?
Copper and aluminium are metals that are excellent conductors of electricity and are also ductile, meaning they can be easily drawn into thin wires.
Which non-metal is a good conductor of electricity?
Graphite, a form of carbon, is a non-metal that can conduct electricity.
Why do metals lose their shine and appear dull over time?
Metals react with moisture, oxygen, and gases present in the air to form a dull layer of oxide on their surface.
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