Class 10 Science Chapter 3 Notes: Metals and Non-Metals

Class 10 Science Chapter 3 Metals and Non-Metals Notes

🔹 1. Metals

Metals are elements which:

• Conduct heat and electricity

• Are malleable and ductile

• Lose electrons to form positive ions (cations)
  ➡️ Hence, metals are called electropositive elements.

Examples

Iron (Fe), Aluminium (Al), Copper (Cu), Silver (Ag), Gold (Au), Sodium (Na), Potassium (K), Calcium (Ca), Magnesium (Mg)

---

🔹 2. Physical Properties of Metals

• Hardness: Generally hard
  (Exception: Na, K are soft)

• Strength: High tensile strength

• State: Solid at room temperature
  (Exception: Mercury – liquid)

• Sonorous: Produce ringing sound

• Conduction: Good conductors of heat & electricity

• Malleability: Can be beaten into thin sheets

• Ductility: Can be drawn into wires

• Melting/Boiling Point: Generally high

• Density: Generally high

• Colour: Mostly grey
  (Exceptions: Gold, Copper)

---

🔹 3. Chemical Properties of Metals

(i) Reaction with Oxygen

Metal + Oxygen → Metal Oxide

• Most metal oxides are basic in nature

• Alkali metals react vigorously

---

(ii) Reaction of Metals with Water

Metal + Water → Metal Hydroxide + Hydrogen

Metal	Reaction with Water
K, Na	Very vigorous
Ca	Slow
Mg	Very slow
Al, Zn, Fe	With steam
Cu, Ag, Au	No reaction

📝 Ca and Mg float on water due to hydrogen bubbles.

---

(iii) Reaction with Dilute Acids

Metal + Dilute Acid → Salt + Hydrogen

✔ Used to prepare H₂ gas in lab

❌ Nitric acid does not liberate hydrogen (strong oxidising agent)

---

(iv) Reactivity Series

Order of decreasing reactivity:

K > Na > Ca > Mg > Al > Zn > Fe > Pb > Cu > Ag > Au

• Cu, Ag, Au → Noble metals

---

(v) Displacement Reaction

A more reactive metal displaces a less reactive one.

Metal A + Salt of Metal B → Salt of A + Metal B

Example:

Fe + CuSO₄ → FeSO₄ + Cu

---

🔹 4. Metal Oxides

• Basic in nature

• Turn red litmus blue

Reaction with Water

Na₂O + H₂O → 2NaOH

Amphoteric Oxides

Oxides that show both acidic and basic behaviour:

• ZnO, Al₂O₃

---

🔹 5. Non-Metals

Non-metals are elements which:

• Do not conduct electricity

• Are neither malleable nor ductile

• Gain electrons to form negative ions (anions)
  ➡️ Called electronegative elements

Examples

Carbon (C), Sulphur (S), Oxygen (O), Nitrogen (N), Chlorine (Cl)

---

🔹 6. Physical Properties of Non-Metals

• Hardness: Generally soft
  (Exception: Diamond)

• State: Solid, liquid or gas

• Lustre: Dull
  (Exception: Iodine, diamond)

• Sonority: Non-sonorous

• Conduction: Poor conductors
  (Exception: Graphite)

• Melting/Boiling Point: Low

• Density: Low

• Colour: Various colours

---

🔹 7. Chemical Properties of Non-Metals

(i) Reaction with Oxygen

Non-metal + Oxygen → Non-metal Oxide

• Non-metal oxides are acidic

---

(ii) Reaction with Hydrogen

Forms covalent hydrides

Examples:

• H₂S, NH₃

---

(iii) Reaction with Chlorine

Non-metal + Cl₂ → Non-metal Chloride

---

Key Points

• Non-metals do not react with water

• Non-metals do not react with dilute acids

---

🔹 8. Ionic Bond and Ionic Compounds

Ions

• Cations: Positive ions (loss of electrons)

• Anions: Negative ions (gain of electrons)

Ionic Bond

Bond formed due to transfer of electrons from metal to non-metal.

Example: NaCl

---

Properties of Ionic Compounds

• Solid and brittle

• High melting & boiling point

• Soluble in water

• Conduct electricity in molten or aqueous state

---

🔹 9. Occurrence of Metals

• Found in earth’s crust and seawater

• Occur as minerals

• Ores → Minerals from which metals can be extracted profitably

---

🔹 10. Extraction of Metals

Main Steps

1. Concentration of ore

2. Conversion into oxide

3. Reduction

4. Refining

---

(i) Concentration of Ores

Removal of impurities (gangue)
Methods:

• Gravity separation

• Froth flotation

• Magnetic separation

---

(ii) Roasting and Calcination

Roasting	Calcination
Sulphide ores	Carbonate ores
Heated in air	Heated without air
SO₂ released	CO₂ released

---

(iii) Reduction

Least Reactive Metals

Hg, Cu → obtained by heating their ores

Medium Reactive Metals

Zn, Fe, Pb → reduced using carbon or aluminium

Thermite Reaction:

Fe₂O₃ + Al → Al₂O₃ + Fe + Heat

---

Highly Reactive Metals

Na, K, Ca, Mg → extracted by electrolysis

---

🔹 11. Refining of Metals

Done by Electrolytic Refining

• Impure metal → Anode

• Pure metal → Cathode

• Impurities settle as anode mud

---

🔹 12. Corrosion

Slow destruction of metals due to air and moisture.

Rusting of Iron

Fe + O₂ + H₂O → Rust

Prevention

• Painting

• Greasing

• Galvanisation

• Electroplating

• Alloying

---

🔹 13. Alloys

Homogeneous mixture of metals or metal + non-metal.

Types

• Ferrous alloys: Steel

• Non-ferrous alloys: Brass, Bronze

• Amalgams: Mercury alloys

Properties

• Stronger than pure metals

• More corrosion resistant

• Lower melting point

• Lower electrical conductivity

---

🔹 14. Metals vs Non-Metals (Quick Comparison)

Metals	Non-Metals
Malleable & ductile	Brittle
Good conductors	Poor conductors
Sonorous	Non-sonorous
Form basic oxides	Form acidic oxides

---

✨ One-Line Revision

• Metals lose electrons, non-metals gain electrons

• Ionic bond = transfer of electrons

• Metal oxides → basic

• Non-metal oxides → acidic

✍️ Top 10 Short Question–Answers

Q1. What are metals?
Ans: Metals are elements that conduct heat and electricity and lose electrons to form positive ions.

Q2. Why are metals called electropositive elements?
Ans: Because metals lose electrons to form positive ions (cations).

Q3. Name any two physical properties of metals.
Ans: Metals are malleable and good conductors of electricity.

Q4. Which metal is liquid at room temperature?
Ans: Mercury.

Q5. What happens when metals react with oxygen?
Ans: Metals form metal oxides which are generally basic in nature.

Q6. What is reactivity series?
Ans: It is the arrangement of metals in decreasing order of their reactivity.

Q7. What is a displacement reaction?
Ans: A reaction in which a more reactive metal displaces a less reactive metal from its compound.

Q8. What are non-metals?
Ans: Non-metals are elements that gain electrons to form negative ions.

Q9. What is an ionic bond?
Ans: An ionic bond is formed by transfer of electrons from a metal to a non-metal.

Q10. What is corrosion?
Ans: Corrosion is the slow destruction of metals due to air and moisture.

---

📝 Long Answer Questions

Q1. Describe the physical and chemical properties of metals.

Ans:

Physical Properties of Metals:

• Generally hard (except Na and K)

• Malleable and ductile

• Good conductors of heat and electricity

• Sonorous in nature

• Usually solid at room temperature

Chemical Properties of Metals:

• React with oxygen to form basic oxides

• React with water to form metal hydroxide and hydrogen

• React with dilute acids to form salt and hydrogen

• Participate in displacement reactions

---

Q2. Explain the properties of non-metals.

Ans:

Physical Properties:

• Generally soft (except diamond)

• Poor conductors of electricity

• Non-sonorous

• Low melting and boiling points

Chemical Properties:

• React with oxygen to form acidic oxides

• React with hydrogen to form covalent hydrides

• Do not react with water or dilute acids

---

Q3. Explain extraction and refining of metals.

Ans:

Extraction of Metals:

• Concentration of ore

• Conversion of ore into oxide

• Reduction of oxide to metal

• Refining of metal

Refining of Metals:

• Done by electrolytic refining

• Impure metal acts as anode

• Pure metal is deposited at cathode

• Impurities collect as anode mud

📝 PYQs (Previous Years’ Questions)

---

🔹 1 Mark PYQs

1. Name the metal which is liquid at room temperature.

2. What type of ions are formed by metals?

3. Name one non-metal which conducts electricity.

4. What is corrosion?

5. Write the chemical formula of rust.

6. What is an alloy?

7. Name one amphoteric oxide.

8. Which metals are called noble metals?

---

🔹 2 Marks PYQs

9. Define malleability and ductility.

10. What is reactivity series? Write one use.

11. Why sodium and potassium are stored in kerosene oil?

12. What is an ionic bond?

13. Why metals are good conductors of electricity?

14. Write two properties of non-metals.

15. What is ore?

---

🔹 3 Marks PYQs

16. Write any three physical properties of metals.

17. Explain reaction of metals with water with examples.

18. What is displacement reaction? Write one equation.

19. Differentiate between metals and non-metals (any three points).

20. Write properties of ionic compounds.

21. What are amphoteric oxides? Give examples.

---

🔹 5 Marks PYQs

22. Explain extraction of metals from ores.

23. Describe the reactivity series and its applications.

24. Explain corrosion and methods of its prevention.

25. What are alloys? Explain types and properties of alloys.

26. Describe electrolytic refining of metals with a diagram.

27. Explain chemical properties of non-metals.

---

⭐ Very Important Repeated PYQs

• Why aluminium is used in thermite reaction?

• Why nitric acid does not liberate hydrogen gas with metals?

• Identify the type of reaction:
  Fe + CuSO₄ → FeSO₄ + Cu

• Why ionic compounds conduct electricity in molten state only?

---

❓ FAQs (Concept Clarity – 5)

Q1. Why sodium and potassium are highly reactive metals?
Ans: Because they are at the top of the reactivity series.

Q2. Why Ca and Mg float on water?
Ans: Due to formation of hydrogen gas bubbles on their surface.

Q3. Why non-metals do not conduct electricity?
Ans: Because they do not have free electrons.

Q4. Why ionic compounds conduct electricity in molten state?
Ans: Because ions are free to move in molten state.

Q5. Why alloys are stronger than pure metals?
Ans: Because alloys have improved physical properties compared to pure metals.