Class 7 Science - ODISHA
The World of Metals and Non-metals
The chapter 'The World of Metals and Non-metals' in Class 7 Science under the Odisha BSE syllabus introduces students to the fundamental building blocks of materials around us. Students explore the physical and chemical properties that distinguish metals like iron, copper, and aluminium from non-metals like carbon, sulphur, and oxygen. The chapter covers concepts such as malleability, ductility, conduction of heat and electricity, and reactions with oxygen and water. Understanding this chapter is crucial for board exam preparation as it forms the basis for higher-level chemistry concepts, frequently appearing in objective questions, short answers, and reasoning-based problems.
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 soft, non-lustrous (dull), brittle, poor conductors of heat and electricity, and cannot be beaten into sheets or drawn into wires.
Reaction with Oxygen
Metals react with oxygen to form basic oxides, while non-metals react with oxygen to form acidic or neutral oxides.
Reaction with Water and Acids
Many metals react with water and acids to produce hydrogen gas, whereas most non-metals do not react with water or dilute acids.
Displacement Reactions
A more reactive metal displaces a less reactive metal from its salt solution in water.
Important Formulas
Board Exam Info
In the Odisha BSE Class 7 Science examinations, this chapter typically carries around 6 to 8 marks. Questions usually include multiple-choice questions (MCQs), fill in the blanks, 'give reasons' type questions (such as why electrical wires are made of copper), and short descriptive questions explaining the differences between metals and non-metals.
Frequently Asked Questions
Why are electrical wires made of copper or aluminium?
Copper and aluminium are metals that have high electrical conductivity and good ductility, allowing them to be drawn into thin wires easily without breaking.
Which non-metal is liquid at room temperature?
Bromine is the only non-metal that exists in a liquid state at room temperature (just as mercury is the only liquid metal).
Why do we store sodium metal in kerosene?
Sodium is an extremely reactive metal that catches fire spontaneously when it comes in contact with moisture and oxygen in the air. To prevent this, it is stored immersed in kerosene.
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