Class 10 Science
Chapter – Metals and Non-metals
Introduction to Metals and Non-metals
CBSE • Foundation • Competitive Level | Hindi + English
Introduction to Metals and Non-metals – धातु एवं अधातु का परिचय
📘 1. Introduction / परिचय
Metals / धातु:
Metals are elements that generally have lustre, are malleable, ductile and good conductors of heat and electricity.
धातु वे तत्व हैं जिनमें सामान्यतः चमक होती है तथा वे आघातवर्धनीय (Malleable), तन्य (Ductile) और ऊष्मा एवं विद्युत के अच्छे चालक होते हैं।
Examples: Iron (Fe), Copper (Cu), Aluminium (Al), Zinc (Zn), Sodium (Na).
Metals are elements that generally have lustre, are malleable, ductile and good conductors of heat and electricity.
धातु वे तत्व हैं जिनमें सामान्यतः चमक होती है तथा वे आघातवर्धनीय (Malleable), तन्य (Ductile) और ऊष्मा एवं विद्युत के अच्छे चालक होते हैं।
Examples: Iron (Fe), Copper (Cu), Aluminium (Al), Zinc (Zn), Sodium (Na).
Non-metals / अधातु:
Non-metals generally do not show metallic properties. Many are poor conductors of heat and electricity and are usually brittle when solid.
अधातु सामान्यतः धात्विक गुण नहीं दिखाते। ठोस अवस्था में अधिकांश अधातु भंगुर होते हैं और ऊष्मा तथा विद्युत के कुचालक होते हैं।
Examples: Carbon (C), Sulphur (S), Oxygen (O), Nitrogen (N), Chlorine (Cl).
Non-metals generally do not show metallic properties. Many are poor conductors of heat and electricity and are usually brittle when solid.
अधातु सामान्यतः धात्विक गुण नहीं दिखाते। ठोस अवस्था में अधिकांश अधातु भंगुर होते हैं और ऊष्मा तथा विद्युत के कुचालक होते हैं।
Examples: Carbon (C), Sulphur (S), Oxygen (O), Nitrogen (N), Chlorine (Cl).
🔬 2. Physical Properties of Metals / धातुओं के भौतिक गुण
1. Lustre / चमक:
Metals generally have a shiny surface when freshly prepared.
2. Malleability / आघातवर्धनीयता: Metals can be beaten into thin sheets.
3. Ductility / तन्यता: Metals can be drawn into wires.
4. Good conductors: Metals generally conduct heat and electricity well.
5. Sonorous: Many metals produce a ringing sound when struck.
6. Generally hard: Many metals are hard, though exceptions such as sodium and potassium are soft.
2. Malleability / आघातवर्धनीयता: Metals can be beaten into thin sheets.
3. Ductility / तन्यता: Metals can be drawn into wires.
4. Good conductors: Metals generally conduct heat and electricity well.
5. Sonorous: Many metals produce a ringing sound when struck.
6. Generally hard: Many metals are hard, though exceptions such as sodium and potassium are soft.
🔬 3. Physical Properties of Non-metals / अधातुओं के भौतिक गुण
• Generally dull, although iodine is lustrous.
• Generally brittle in solid state.
• Generally poor conductors of heat and electricity.
• Generally not sonorous.
• Usually not malleable or ductile.
• May exist as solids, liquids or gases.
Examples of exceptions:
Graphite conducts electricity.
Iodine has lustre.
Bromine is a liquid non-metal.
• Generally brittle in solid state.
• Generally poor conductors of heat and electricity.
• Generally not sonorous.
• Usually not malleable or ductile.
• May exist as solids, liquids or gases.
Examples of exceptions:
Graphite conducts electricity.
Iodine has lustre.
Bromine is a liquid non-metal.
⚖️ 4. Metals vs Non-metals / धातु एवं अधातु में अंतर
| Property / गुण | Metals / धातु | Non-metals / अधातु |
|---|---|---|
| Lustre / चमक | Generally lustrous | Generally dull |
| Malleability | Generally malleable | Generally brittle |
| Ductility | Generally ductile | Generally non-ductile |
| Conductivity | Generally good conductors | Generally poor conductors |
| Sonority | Generally sonorous | Generally non-sonorous |
| Oxides | Generally basic | Generally acidic or neutral |
⚗️ 5. Chemical Properties of Metals / धातुओं के रासायनिक गुण
Metals commonly react with oxygen, water, acids and other substances.
Reaction with oxygen:
Reaction with oxygen:
2Mg + O₂ → 2MgO
Magnesium forms magnesium oxide, which is basic in nature.
Reaction with water: Some metals react with water to form hydroxides/oxides and hydrogen.
Reaction with water: Some metals react with water to form hydroxides/oxides and hydrogen.
2Na + 2H₂O → 2NaOH + H₂
Reaction with acids:
Many metals react with dilute acids to produce salt and hydrogen gas.
Zn + 2HCl → ZnCl₂ + H₂
⚗️ 6. Chemical Properties of Non-metals / अधातुओं के रासायनिक गुण
Non-metals generally react with oxygen to form acidic or neutral oxides.
Example:
Example:
C + O₂ → CO₂
Carbon dioxide is an acidic oxide.
Sulphur also forms an acidic oxide:
Sulphur also forms an acidic oxide:
S + O₂ → SO₂
⚡ 7. Formation of Ions / आयनों का निर्माण
Metals generally lose electrons to form positive ions called cations.
Example:
Example:
Na → Na⁺ + e⁻
Non-metals generally gain electrons to form negative ions called anions.
Example:
Example:
Cl + e⁻ → Cl⁻
🎯 8. Electropositive and Electronegative Nature
Metals are generally electropositive because they tend to lose
electrons.
Non-metals are generally electronegative because they tend to gain electrons.
Non-metals are generally electronegative because they tend to gain electrons.
🎯 30 MCQ – Multiple Choice Questions
✍️ 30 Subjective Questions – 1 to 6 Marks
1 Mark
1. What is a metal? / धातु क्या है?
1. What is a metal? / धातु क्या है?
A metal is an element that generally shows metallic properties such
as lustre, malleability, ductility and electrical conductivity.
धातु वह तत्व है जिसमें सामान्यतः चमक, आघातवर्धनीयता, तन्यता तथा विद्युत चालकता जैसे गुण पाए जाते हैं।
धातु वह तत्व है जिसमें सामान्यतः चमक, आघातवर्धनीयता, तन्यता तथा विद्युत चालकता जैसे गुण पाए जाते हैं।
1 Mark
2. Give one example of a metal.
2. Give one example of a metal.
Iron (Fe).
1 Mark
3. Give one example of a non-metal.
3. Give one example of a non-metal.
Sulphur (S).
1 Mark
4. What is malleability?
4. What is malleability?
The property of metals by which they can be beaten into thin sheets
is called malleability.
1 Mark
5. What is ductility?
5. What is ductility?
The property of being drawn into thin wires is called ductility.
2 Marks
6. Give two physical properties of metals.
6. Give two physical properties of metals.
Metals are generally lustrous and good conductors of heat and
electricity.
2 Marks
7. Give two physical properties of non-metals.
7. Give two physical properties of non-metals.
Most non-metals are brittle in solid state and poor conductors of
heat and electricity.
2 Marks
8. Why are metals used for making electrical wires?
8. Why are metals used for making electrical wires?
Because metals such as copper and aluminium are good conductors of
electricity and can be drawn into wires due to ductility.
2 Marks
9. Why can metals be made into sheets?
9. Why can metals be made into sheets?
Because metals possess the property of malleability.
2 Marks
10. Name one lustrous non-metal and one conducting non-metal.
10. Name one lustrous non-metal and one conducting non-metal.
Iodine is a lustrous non-metal, while graphite is a non-metal that
conducts electricity.
3 Marks
11. Write three differences between metals and non-metals.
11. Write three differences between metals and non-metals.
1. Metals are generally lustrous; non-metals are generally dull.
2. Metals are generally malleable; solid non-metals are generally brittle.
3. Metals generally conduct electricity well; non-metals generally do not.
2. Metals are generally malleable; solid non-metals are generally brittle.
3. Metals generally conduct electricity well; non-metals generally do not.
3 Marks
12. Explain malleability, ductility and sonority.
12. Explain malleability, ductility and sonority.
Malleability: Ability to form thin sheets.
Ductility: Ability to form wires.
Sonority: Ability to produce a ringing sound when struck.
Ductility: Ability to form wires.
Sonority: Ability to produce a ringing sound when struck.
3 Marks
13. Why are metals good conductors of electricity?
13. Why are metals good conductors of electricity?
Metals contain mobile or delocalised electrons that can move through
the metallic structure and carry electric charge.
3 Marks
14. Explain why graphite is an exception among non-metals.
14. Explain why graphite is an exception among non-metals.
Graphite is a form of carbon. It contains electrons that can move
along its layered structure, so graphite conducts electricity despite
being a non-metal.
3 Marks
15. Write three chemical properties of metals.
15. Write three chemical properties of metals.
Metals react with oxygen, some react with water, and many react with
dilute acids to form salts and hydrogen.
4 Marks
16. Explain the reaction of metals with oxygen.
16. Explain the reaction of metals with oxygen.
Metals generally react with oxygen to form metal oxides.
Example:
Example:
2Mg + O₂ → 2MgO
Magnesium oxide is generally basic in nature.
4 Marks
17. Explain the reaction of metals with dilute acids.
17. Explain the reaction of metals with dilute acids.
Many metals react with dilute acids to form salt and hydrogen gas.
Example:
Example:
Zn + 2HCl → ZnCl₂ + H₂
The evolution of hydrogen can be observed as bubbles.
4 Marks
18. Explain why sodium is stored in kerosene.
18. Explain why sodium is stored in kerosene.
Sodium is highly reactive and reacts vigorously with oxygen and water.
Kerosene prevents direct contact with air and moisture.
4 Marks
19. Explain the formation of Na⁺ and Cl⁻ ions.
19. Explain the formation of Na⁺ and Cl⁻ ions.
Sodium loses one electron:
Na → Na⁺ + e⁻
Chlorine gains one electron:
Cl + e⁻ → Cl⁻
Thus sodium forms a cation and chlorine forms an anion.
4 Marks
20. Why are non-metals generally poor conductors?
20. Why are non-metals generally poor conductors?
Non-metals generally do not have freely mobile charge carriers.
Therefore, most non-metals do not conduct electricity efficiently.
Graphite is an important exception.
5 Marks
21. Describe the important physical properties of metals.
21. Describe the important physical properties of metals.
Important properties include:
1. Metals are generally lustrous.
2. They are generally malleable.
3. They are generally ductile.
4. They are generally good conductors of heat and electricity.
5. Many metals are sonorous.
1. Metals are generally lustrous.
2. They are generally malleable.
3. They are generally ductile.
4. They are generally good conductors of heat and electricity.
5. Many metals are sonorous.
5 Marks
22. Describe the important physical properties of non-metals.
22. Describe the important physical properties of non-metals.
Non-metals are generally dull, brittle in solid state, non-malleable,
non-ductile and poor conductors of heat and electricity. However,
exceptions exist, such as lustrous iodine and conducting graphite.
5 Marks
23. Explain the chemical behaviour of metals with examples.
23. Explain the chemical behaviour of metals with examples.
Metals react with oxygen to form oxides:
2Mg + O₂ → 2MgO
Some metals react with water:
2Na + 2H₂O → 2NaOH + H₂
Many metals react with dilute acids:
Zn + 2HCl → ZnCl₂ + H₂
5 Marks
24. Explain why metals form positive ions.
24. Explain why metals form positive ions.
Metals generally have a tendency to lose their valence electrons.
Loss of electrons gives them a positive charge, so they form cations.
Example:
Na → Na⁺ + e⁻
6 Marks
25. Compare metals and non-metals on the basis of physical properties.
25. Compare metals and non-metals on the basis of physical properties.
Metals:
• Generally lustrous
• Malleable
• Ductile
• Good conductors
• Generally sonorous
Non-metals:
• Generally dull
• Brittle in solid state
• Non-ductile
• Generally poor conductors
• Generally non-sonorous
• Generally lustrous
• Malleable
• Ductile
• Good conductors
• Generally sonorous
Non-metals:
• Generally dull
• Brittle in solid state
• Non-ductile
• Generally poor conductors
• Generally non-sonorous
6 Marks
26. Explain the formation of ionic compounds using NaCl as an example.
26. Explain the formation of ionic compounds using NaCl as an example.
Sodium has one valence electron and chlorine needs one electron to
complete its outer shell.
Sodium loses an electron:
Sodium loses an electron:
Na → Na⁺ + e⁻
Chlorine gains that electron:
Cl + e⁻ → Cl⁻
The oppositely charged ions attract each other and form NaCl.
Thus NaCl is an ionic compound.
6 Marks
27. Explain the reactions of metals with oxygen, water and acids.
27. Explain the reactions of metals with oxygen, water and acids.
With oxygen:
2Mg + O₂ → 2MgO
With water:
2Na + 2H₂O → 2NaOH + H₂
With acid:
Zn + 2HCl → ZnCl₂ + H₂
These reactions demonstrate the chemical reactivity of metals.
6 Marks
28. Explain important exceptions to the general properties of metals and non-metals.
28. Explain important exceptions to the general properties of metals and non-metals.
General rules have important exceptions.
1. Sodium and potassium are metals but are very soft.
2. Mercury is a metal but is liquid at room temperature.
3. Graphite is a non-metal but conducts electricity.
4. Iodine is a non-metal but has lustre.
5. Bromine is a liquid non-metal at room temperature.
1. Sodium and potassium are metals but are very soft.
2. Mercury is a metal but is liquid at room temperature.
3. Graphite is a non-metal but conducts electricity.
4. Iodine is a non-metal but has lustre.
5. Bromine is a liquid non-metal at room temperature.
6 Marks
29. Explain why metals are useful for making different objects.
29. Explain why metals are useful for making different objects.
Metals are useful because of their combination of physical properties.
Their malleability allows them to be shaped into sheets, ductility
allows wire formation, strength makes them useful in structures and
their high electrical conductivity makes them useful in electrical
applications.
6 Marks
30. Write a comprehensive note on metals and non-metals.
30. Write a comprehensive note on metals and non-metals.
Metals and non-metals are two major groups of elements.
Metals generally possess lustre, malleability, ductility, sonority and good electrical and thermal conductivity. They generally lose electrons and form positive ions.
Non-metals generally lack these metallic properties. They are usually brittle in solid state and poor conductors. They generally gain electrons and form negative ions.
Important exceptions include graphite, iodine, mercury, sodium and potassium.
Metals generally possess lustre, malleability, ductility, sonority and good electrical and thermal conductivity. They generally lose electrons and form positive ions.
Non-metals generally lack these metallic properties. They are usually brittle in solid state and poor conductors. They generally gain electrons and form negative ions.
Important exceptions include graphite, iodine, mercury, sodium and potassium.
