Class 7 Science - MAHARASHTRA
The World of Metals and Non-metals
The chapter 'The World of Metals and Non-metals' in Class 7 Science introduces MSBSHSE students to the fascinating classification of elements based on their physical and chemical properties. Students learn about the distinct characteristics of metals, such as malleability, ductility, electrical conductivity, and sonority, contrasted with brittle and dull non-metals. The chapter also covers metalloids, which show properties of both. Understanding these materials is vital for board exams as it builds the foundational chemical knowledge required for higher classes, explaining why copper is used for wires and iron for construction.
Start Learning FreeKey Concepts
Physical Properties of Metals
Metals are generally solid, 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 can be solid, liquid, or gas, and they lack luster, malleability, and ductility. They are generally poor conductors of heat and electricity and are brittle.
Metalloids
Elements that show properties of both metals and non-metals are called metalloids, such as silicon, arsenic, and germanium.
Corrosion
The process by which metals are slowly eaten away by the action of air, moisture, or chemicals on their surface, such as rusting of iron.
Noble Gases
A special group of non-metals that are unreactive and exist as gases in nature, such as helium, neon, and argon.
Important Formulas
Board Exam Info
In the Maharashtra (MSBSHSE) Class 7 Science examinations, this chapter typically carries around 4 to 6 marks. Common question types include fill in the blanks, distinguishing between metals and non-metals, giving scientific reasons (e.g., why wires are made of copper), and short-answer questions defining terms like malleability and corrosion.
Frequently Asked Questions
Are all metals solid at room temperature?
No, mercury is a metal that is liquid at room temperature.
Why do copper vessels turn green over time?
Copper reacts with moist carbon dioxide in the air to form a green coating of basic copper carbonate, which is a type of corrosion.
Can non-metals conduct electricity?
Most non-metals cannot conduct electricity, but graphite, a form of carbon, is an exception and can conduct electricity.
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