The World of Metals and Non metals Class 7 Notes

The World of Metals and Non metals Class 7 Notes

The World of Metals and Non metals Class 7 Notes

1. Metals: Elements that are typically shiny, malleable, ductile, and good conductors of heat and electricity.
2. Non-metals: Elements that are generally not shiny, brittle, and poor conductors of heat and electricity.
3. Malleability: The physical property by which materials can be beaten into thin sheets is called malleability.
4. Ductility: The property by which they can be drawn into wires is called ductility.
5. Corrosion: The gradual destruction of materials (usually metals) by chemical reactions with their environment, often involving moisture and oxygen.
6. Oxides: Compounds formed when elements react with oxygen.
7. Alloys: Mixtures of two or more metals or a metal and a non-metal.
8. Conductivity: The ability of a material to conduct heat or electricity.
9. Reactivity: The tendency of a substance to undergo a chemical reaction, either by itself or with other materials.
10. Sustainability: The practice of using resources in a way that does not deplete them and allows for long-term ecological balance.
11. Essential Nutrients: Substances that are necessary for the growth and maintenance of living organisms.
12. Ironsmiths: A skilled metalworker who crafts objects from iron and steel.
13. Craftsperson: A person who practices a trade or handicraft as a job.
14. Luster: Metal are lustrous (shine) in appearance. Examples: Copper, aluminium, iron.
15. Flattened: To become thinner
16. Suspension bridges: A type of bridge in which the deck is hung below suspension cables on vertical suspenders.
17. Scrubbing: To rub a surface hard, to clean it.
18. Rusting: The chemical process that causes a red or orange coating to form on the surface of metals.
19. Discolouration: A change to the original colour of something that makes it look unpleasant or damaged.
20. Deterioration: To become impaired in quality or condition.
21. Enormous: Extraordinarily great in size or number.
22. Galvanisation: The process of applying a protective zinc coating to steel or iron to prevent rusting.
23. Vigorously: With force and energy.
24. Deflagrating: To burn rapidly with intense heat and sparks being given off.
25. Antiseptic: Opposing microbial infection.

1. Metals

A. Properties

1. Lustrous: Metals like copper, aluminium, and iron exhibit metallic lustre.
2. Hardness: Most metals are hard, but some (e.g., sodium, potassium) are soft.
3. Malleability: Ability to be beaten into thin sheets (e.g., aluminium foil, gold leaf).
4. Ductility: Ability to be drawn into wires (e.g., copper wires).
5. Heat and electrical conductivity: Good conductor of heat and electricity (e.g., copper and aluminium)
6. Sonorous: Most metals produce a ringing sound when struck hard (e.g., copper and iron)

B. Examples of Metals

1. Copper, Aluminium, Iron, Gold, Silver C. Applications
2. Tools (e.g., axes, ploughs), Electrical wiring, Jewellery.
3. Historical Context: The significance of iron in the development of civilization, particularly in agriculture.

2. Non-metals

A. Properties

1. Non-lustrous: Generally, do not have a shiny appearance (e.g., sulfur, coal).
2. Brittleness: Many non-metals break easily when hammered (e.g., sulfur, coal).
3. Softness: Generally softer than metals (except diamond).
4. Heat and electrical conductivity: Most non-metals are poor conductor of heat and electricity (except graphite)

B. Examples of Non-metals

Sulfur, Coal, Wood and stone etc.

C. Applications

Used in various chemical processes, Fuel sources (e.g., coal)

Comparative Analysis Metals vs. Non-metals Metals are generally lustrous, hard, malleable, ductile and good conductor of heat and electricity.

Non-metals are typically non-lustrous, brittle, softer, non-malleable, non-ductile and poor conductor of heat and electricity.