Chapter 3: Metals and Non‑Metals: Essential Notes for Class 10 Science Exams
Welcome to your quick revision guide on Metals and Non‑Metals—one of the most important chapters in CBSE Class 10 Science. These exam-focused notes will help you understand core concepts, remember key reactions, and score high marks in your upcoming board exams. Written in simple language, this article is optimized for SEO with high‑paying keywords like “Class 10 Science exam preparation,” “Metals and Non‑Metals notes,” and “CBSE Chapter 3 quick revision.”
1. Introduction to Metals and Non‑Metals
In Chapter 3 of your Class 10 Science book, you’ll learn to distinguish between metals and non‑metals based on their physical and chemical properties. Metals are generally lustrous, malleable, ductile, and good conductors of heat and electricity. Non‑metals tend to be brittle (in solid state), lack shine, and are poor conductors. Understanding these properties is crucial for CBSE board exams.
2. Physical Properties of Metals
Key physical traits of metals include:
2.1 Lustre
Most metals have a shiny surface when freshly cut. This metallic lustre helps identify metals like iron, copper, and silver.
2.2 Malleability and Ductility
Metals can be beaten into thin sheets (malleability) and drawn into wires (ductility). For example, gold is highly ductile and malleable, making it ideal for jewelry and electronics.
2.3 Conductivity
Metals conduct heat and electricity efficiently. Copper and aluminum are commonly used in electrical wiring due to their excellent conductivity.
2.4 Hardness and Density
Most metals are hard and have high density. Tungsten, for instance, has one of the highest melting points and is extremely dense, making it useful in light bulb filaments.
3. Physical Properties of Non‑Metals
3.1 Appearance
Non‑metals lack metallic lustre and are often dull. Carbon in the form of graphite appears lustrous, but this is an exception.
3.2 Brittleness
When struck, non‑metals break or shatter rather than bending. This brittleness distinguishes them from metals.
3.3 Conductivity
Non‑metals are poor conductors of heat and electricity. Sulfur and phosphorus are good insulators.
3.4 State and Density
Non‑metals can exist in solid, liquid, or gaseous states at room temperature (e.g., iodine is solid, bromine is liquid, and chlorine is gas). They generally have low density compared to metals.
4. Chemical Properties of Metals
Metals undergo characteristic reactions that are frequently asked in Class 10 Science exams. Remember these three key reactions:
4.1 Reaction with Oxygen
Most metals form metal oxides on heating in oxygen. For example:
2Mg + O2 → 2MgO
4.2 Reaction with Water
Highly reactive metals like sodium and potassium react violently with water:
2Na + 2H2O → 2NaOH + H2
Less reactive metals like iron react slowly, and some (like gold) do not react at all.
4.3 Reaction with Acids
Most metals dissolve in dilute acids to produce hydrogen gas:
Zn + 2HCl → ZnCl2 + H2
This reaction is very important—question setters often ask for the gas evolution and metal salt formed.
5. Chemical Properties of Non‑Metals
5.1 Reaction with Oxygen
Non‑metals like sulfur burn in oxygen to form acidic oxides:
S + O2 → SO2
5.2 Reaction with Hydrogen
Many non‑metals react with hydrogen to form covalent hydrides. For example:
Cl2 + H2 → 2HCl
5.3 Reaction with Metals
Non‑metals react with metals to form ionic compounds. For instance:
2Na + Cl2 → 2NaCl
6. Activity Series of Metals (Reactivity Series)
The reactivity series ranks metals by their ability to displace other metals from solutions. From most reactive to least:
K > Na > Ca > Mg > Al > Zn > Fe > Pb > H > Cu > Ag > Au
Use this series to predict whether a metal will react with water, acids, or metal salts. Questions often ask you to explain displacement reactions based on this series.
7. Occurrence and Extraction of Metals
Metals are found in the Earth’s crust as ores. Extraction processes vary by metal reactivity:
7.1 Extraction of Less Reactive Metals
Ores of metals below carbon in the reactivity series are reduced using carbon (coke) in a blast furnace. Example:
Fe2O3 + 3C → 2Fe + 3CO
7.2 Extraction of Highly Reactive Metals
Ores of reactive metals like aluminium are extracted by electrolysis. Remember the Hall–Héroult process for aluminium:
2Al2O3 → 4Al + 3O2 (electrolytic reduction)
Understanding these processes in simple steps is key to scoring in Class 10 board exams.
8. Corrosion and Its Prevention
Corrosion is the gradual destruction of metals by chemical reaction with atmospheric elements, especially oxygen and moisture. Iron rusts in presence of water and oxygen:
4Fe + 3O2 + 6H2O → 4Fe(OH)3
Preventive methods include:
8.1 Painting and Coating
A layer of paint or plastic prevents exposure to water and oxygen.
8.2 Galvanization
Coating iron with a layer of zinc protects it by sacrificial action.
8.3 Electroplating
Metals like chromium are coated on other metals to prevent corrosion.
9. Uses of Metals and Non‑Metals
Knowing real‑world applications helps in conceptual clarity and exam answers:
9.1 Metals
Copper in electrical wiring, aluminium in aircraft bodies, gold in electronics and jewelry.
9.2 Non‑Metals
Chlorine in disinfectants, sulfur in vulcanization of rubber, carbon in steel factories.
10. Important Exam Tips
– Always write chemical equations with correct symbols and state of matter.
– Highlight observations (e.g., color change, gas evolution) in reaction explanations.
– Use the reactivity series to justify displacement reactions.
– Memorize key processes like Hall–Héroult and blast furnace steps.
11. Summary
This article covered all important notes on Metals and Non‑Metals for CBSE Class 10 Science Chapter 3. Keep these points handy for last‑minute revision. Regularly practise writing balanced equations and definitions to boost your board exam score.
Disclaimer: These notes are meant for quick revision and supplement your NCERT textbook. Always refer to your class notes and consult your teacher for detailed explanations.
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