class 10 Metals and Non Metals
Metals and Non-Metals – CBSE Class 10 Science Notes
Introduction
In Class 10 Science, the chapter Metals and Non-Metals is one of the most important topics for exams. It helps us understand the physical and chemical properties of elements, their uses in daily life, and the differences between metals and non-metals. Let’s explore this chapter in detail.
Physical Properties of Metals
- Lustrous (Shiny) – Metals like gold, silver, and copper have a shiny appearance.
- Hardness – Most metals are hard (except sodium and potassium which are soft).
- Malleability – Can be hammered into thin sheets (e.g., aluminium foil).
- Ductility – Can be drawn into wires (copper wires for electricity).
- Conductivity – Good conductors of heat and electricity.
- High Melting & Boiling Points – Metals usually have high melting points (except mercury and gallium).
- Sonority – Metals produce a ringing sound when struck.
Physical Properties of Non-Metals
- Non-lustrous – Usually dull in appearance (except iodine).
- Brittle – Break easily when hammered.
- Poor Conductors – Do not conduct electricity (except graphite).
- Low Density – Lighter than metals.
- Low Melting & Boiling Points – Except diamond which is very hard.
Chemical Properties of Metals
- Reaction with Oxygen – Metals form metal oxides.
- Example: 4Na + O₂ → 2Na₂O
- Reaction with Water – Some metals react vigorously with water.
- Example: 2Na + 2H₂O → 2NaOH + H₂ ↑
- Reaction with Acids – Metals react with acids to form salt + hydrogen gas.
- Example: Zn + 2HCl → ZnCl₂ + H₂ ↑
- Displacement Reaction – A more reactive metal displaces a less reactive metal from its salt solution.
Chemical Properties of Non-Metals
- Reaction with Oxygen – Non-metals form acidic oxides.
- Example: C + O₂ → CO₂
- Reaction with Hydrogen – Non-metals form covalent compounds.
- Example: H₂ + Cl₂ → 2HCl
- No Reaction with Acids – Non-metals generally do not react with dilute acids.
Metallurgy – Extraction of Metals
- Ores: Minerals from which metals can be extracted.
- Steps of Metallurgy:
- Concentration of ore – Removing impurities.
- Reduction – Obtaining metal from its compound.
- Refining – Purification of the extracted metal.
Uses of Metals
- Iron: Used in construction, machinery.
- Copper: Electrical wires.
- Aluminium: Packaging (foils), airplanes.
- Gold & Silver: Jewelry, coins.
Uses of Non-Metals
- Oxygen: Essential for respiration.
- Nitrogen: Used in fertilizers.
- Chlorine: Used in water purification.
- Sulphur: Used in medicines and fireworks.
Differences Between Metals and Non-Metals
| Property | Metals | Non-Metals |
|---|---|---|
| Appearance | Shiny | Dull |
| Malleability | Can be hammered into sheets | Brittle |
| Conductivity | Good conductors | Poor conductors |
| State | Mostly solid | Solid, liquid or gas |
| Oxides | Basic | Acidic |
Important Questions for Exams
- Why are metals good conductors of electricity?
- Write one example of a displacement reaction.
- Differentiate between metals and non-metals based on physical properties.
- Explain the process of corrosion and its prevention.
Conclusion
The chapter Metals and Non-Metals in Class 10 Science explains how these elements differ in properties and uses. Understanding their reactions and applications is very important for scoring well in CBSE exams as well as in real-life applications.
Here’s a well-researched, student-friendly FAQ section for “Class 10 Metals and Non-Metals”, complete with clear answers. These are pulled from authoritative CBSE-focused websites and academic sources to ensure accuracy and clarity:
FAQ: Class 10 Metals and Non-Metals
Q1: Which gas is produced when a metal reacts with dilute hydrochloric acid?
A: Hydrogen gas (H₂) is produced. Example:
Fe(s) + 2 HCl(dil) → FeCl₂(aq) + H₂(g)
Q2: What happens when zinc is added to a solution of iron(II) sulfate?
A: Zinc, being more reactive than iron, displaces iron from the solution. The solution turns colorless (zinc sulfate), and a greyish iron precipitate forms.
Zn(s) + FeSO₄(aq) → ZnSO₄(aq) + Fe(s)↓
Q3: What are amphoteric oxides? Give examples.
A: Amphoteric oxides act both as acids and bases. For instance, zinc oxide (ZnO) and aluminum oxide (Al₂O₃) react with both acids and bases.
Q4: Why is hydrogen not evolved when most metals react with nitric acid (HNO₃)?
A: Nitric acid is a strong oxidizing agent; it oxidizes any hydrogen formed into water and itself reduces to nitrogen oxides. Therefore, hydrogen gas is typically not observed.
Q5: Why is sodium kept immersed in kerosene?
A: Sodium is highly reactive with air and water, often igniting or causing fire. Immersing it in kerosene prevents contact with air and moisture, ensuring safety.
Q6: Metals are good conductors of electricity. Why?
A: Metals contain free electrons that can move easily through their structure, allowing them to conduct electricity effectively.
Q7: How do metals and non-metals differ in their physical properties?
A:
- Metals: Usually solid (except mercury), lustrous, dense, good conductors of heat and electricity, malleable, and ductile.
- Non-metals: Can be solid, liquid, or gas, generally non-lustrous, less dense, poor conductors, and brittle when solid.
Q8: What type of oxides do metals and non-metals form?
A:
- Metals typically form basic oxides.
- Non-metals form acidic oxides (which turn blue litmus red). For example, CO₂, SO₂.
Q9: Give an example of a metal and a non-metal that are liquid at room temperature.
A: Mercury (metal) and bromine (non-metal) are both liquids at room temperature.
Q10: Which metals don’t corrode easily?
A: Noble metals such as gold, silver, and platinum are highly resistant to corrosion and oxidation.
Summary
- Metals and non-metals exhibit contrasting physical and chemical behaviors.
- Metals are solid (mostly), lustrous, malleable, and excellent conductors.
- Non-metals are often brittle, poor conductors, and form acidic oxides.
- Oxide behavior (basic vs. acidic), conductivity, reactivity, and state at room temperature are key factors in distinguishing them.
