Class VIII – Metals and Non-Metals

-

 

Chapter: Metals and Non-Metals (Class VIII)

1. Metals

  • Metals are elements that are good conductors of heat and electricity.
  • They are generally shiny in appearance.
  • Metals are malleable, which means they can be beaten into thin sheets.
  • Metals are ductile, which means they can be drawn into wires.
  • Most metals are hard and exist in the solid state at room temperature.
  • Exception: Mercury is the only metal that is liquid at room temperature.

2. Non-Metals

  • Non-metals are elements that are poor conductors of heat and electricity.
  • They are generally dull in appearance.
  • Non-metals are brittle and break easily on hammering.
  • They are neither malleable nor ductile.
  • Most non-metals exist in the gaseous or solid state.
  • Exception: Bromine is the only non-metal that is liquid at room temperature.

3. Physical Properties of Metals

  • Shiny appearance
  • Hardness
  • Malleability
  • Ductility
  • Good conductors of heat and electricity
  • Sonorous (produce sound when struck)

4. Physical Properties of Non-Metals

  • Lack of shine
  • Brittleness
  • Poor conductors of heat and electricity
  • Non-sonorous

5. Chemical Properties of Metals

  • Metals react with oxygen to form basic oxides.
  • Example: 2Mg + O₂ → 2MgO
  • Metals react with acids to form salt and hydrogen gas.
  • More reactive metals displace less reactive metals from their compounds.

6. Chemical Properties of Non-Metals

  • Non-metals react with oxygen to form acidic oxides.
  • Non-metals generally gain electrons during chemical reactions.

7. Oxides of Metals and Non-Metals

  • Metal oxides are generally basic in nature.
  • Non-metal oxides are generally acidic in nature.

8. Important Examples

  • Most reactive metal: Sodium
  • Best conductor of electricity: Silver
  • Non-metal that conducts electricity: Graphite
  • Hardest non-metal: Diamond

9. Special Facts

  • Sodium and potassium are stored in kerosene oil because they are highly reactive.
  • Aluminium is used to make food foils because it is malleable and corrosion-resistant.
  • Lemon pickle is not kept in aluminium containers because acids react with aluminium and form harmful substances.

10. Uses

Uses of Metals

  • Making electric wires
  • Making utensils, machines, and tools
  • Construction of buildings and bridges

Uses of Non-Metals

  • Oxygen is used for respiration.
  • Hydrogen is used as a fuel.
  • Chlorine is used in water purification.
  • Iodine is used as an antiseptic.

11. Important Chemical Formulae

  • Copper sulphate – CuSO₄
  • Sodium oxide – Na₂O
  • Magnesium oxide – MgO
  • Sodium chloride – NaCl
  • Magnesium chloride – MgCl₂
  • Sulphuric acid – H₂SO₄

12. Important Reactions

Displacement Reaction

  • Zn + CuSO₄ → ZnSO₄ + Cu

Reaction of Copper with Dilute Sulphuric Acid

  • Copper + dilute sulphuric acid → Copper sulphate + water + sulphur dioxide

Objective Questions with Answers (Facts Only)

  • Copper sulphate is blue in colour.
  • The chemical formula of copper sulphate is CuSO₄.
  • Sulphur is present in gunpowder.
  • Metals are good conductors of heat and electricity.
  • Iodine is a shining non-metal.
  • Sodium is stored in kerosene oil.
  • Oxides of metals are basic.
  • Oxides of non-metals are acidic.
  • Sodium can be cut with a knife.
  • Aluminium is used for food packing.
  • Sodium is the most reactive metal.
  • Mercury is liquid at room temperature.
  • Bromine is a liquid non-metal.
  • Graphite is a conducting non-metal.
  • Malleability allows metals to be beaten into sheets.
  • Ductility allows metals to be drawn into wires.
  • Silver is the best conductor of electricity.
  • Pencil lead is made of graphite.
  • Chlorine is used in water purification.
  • Chlorine is used to make bleaching powder.
  • Lead is used for X-rays.
  • Magnesium is used in fireworks.
  • Mercury is used in thermometers.
  • Gold is the most ductile metal.
  • Brass is an alloy.
  • Phosphorus is the most reactive non-metal.
  • Metals are generally shiny.
  • Non-metals are generally brittle.
  • Metals are good conductors of heat.
  • Non-metals are poor conductors of heat.
  • Lemon pickle is not kept in aluminium containers due to acid reaction.
  • School bells are made of tin.
  • Lohardaga (Jharkhand) is famous for aluminium ore.
  • Jadugoda (Jharkhand) is famous for uranium.
  • Urea contains excess nitrogen.
  • Metals are elements that conduct heat and electricity.
  • Non-metals are elements that do not conduct heat and electricity.
  • Sonority is a property of metals.
  • Oxygen is essential for combustion.
  • Copper sulphate is a compound of copper.


1. What are metals?
Answer: Metals are elements that conduct heat and electricity.

2. Which metal is liquid at room temperature?
Answer: Mercury.

3. What property allows metals to be beaten into thin sheets?
Answer: Malleability.

4. What property allows metals to be drawn into wires?
Answer: Ductility.

5. Are metals generally shiny or dull?
Answer: Shiny.

6. What are non-metals?
Answer: Non-metals are elements that are poor conductors of heat and electricity.

7. Which non-metal is liquid at room temperature?
Answer: Bromine.

8. Are non-metals malleable?
Answer: No, non-metals are not malleable.

9. Which non-metal is a good conductor of electricity?
Answer: Graphite.

10. Which is the hardest non-metal?
Answer: Diamond.

11. What type of oxides are formed by metals?
Answer: Basic oxides.

12. What type of oxides are formed by non-metals?
Answer: Acidic oxides.

13. Which metal is the most reactive?
Answer: Sodium.

14. Why is sodium stored in kerosene oil?
Answer: Because it is highly reactive.

15. Which metal is used to make electric wires?
Answer: Copper.

16. Which metal is the best conductor of electricity?
Answer: Silver.

17. Which metal is used in fireworks?
Answer: Magnesium.

18. Which metal is used in thermometers?
Answer: Mercury.

19. What is the colour of copper sulphate?
Answer: Blue.

20. What is the chemical formula of copper sulphate?
Answer: CuSO₄.

21. Which substance is used for water purification?
Answer: Chlorine.

22. Which gas is essential for respiration?
Answer: Oxygen.

23. Which non-metal is used as an antiseptic?
Answer: Iodine.

24. Which metal is used for making food foil?
Answer: Aluminium.

25. Why should lemon pickle not be kept in aluminium containers?
Answer: Because acids react with aluminium.

26. What is pencil lead made of?
Answer: Graphite.

27. Which metal can be cut with a knife?
Answer: Sodium.

28. What is an alloy?
Answer: An alloy is a mixture of metals.

29. What is brass?
Answer: Brass is an alloy.

30. Which metal is most ductile?
Answer: Gold.

31. Are metals sonorous?
Answer: Yes, metals are sonorous.

32. What does sonorous mean?
Answer: Producing sound when struck.

33. Which metal is used in X-ray shielding?
Answer: Lead.

34. Which non-metal is used in gunpowder?
Answer: Sulphur.

35. What is the nature of metals towards electrons?
Answer: Metals lose electrons.

36. What is the nature of non-metals towards electrons?
Answer: Non-metals gain electrons.

37. Which gas is necessary for combustion?
Answer: Oxygen.

38. Which compound is formed when zinc reacts with copper sulphate?
Answer: Zinc sulphate.

39. Which metal compound is CuSO₄?
Answer: Copper sulphate.

40. What are non-metals generally in nature – hard or brittle?
Answer: Brittle.


Comments

Post a Comment

Popular posts from this blog

koshik question

-
 2  December  Test Results F.M - 14       Top Students .  Laxmi Pandit 9th 14 4 December  Test Results F.M - 10       Top Students .  Anjali 9th -9 Sana 8th - 9 Lalita 9th - 9 Sonali 9th  - 9 Laxmi 9th - 9 5 December   Test Results F.M - 20       Top Students.                 सोनाली कुमारी 9th- 20 ललिता कुमारी 9th -19 खुशी कुमारी 8th- 19 राजन कुमार sing 8th- 19 अंजली कुमारी 9th -19 हिमांशु कुमार 8th - 19 💠 कोशिका – जीवन की इकाई (महत्त्वपूर्ण प्रश्न–उत्तर) प्रश्न : कोशिका क्या है? उत्तर : कोशिका सभी जीवों की सबसे छोटी जीवित इकाई है जो संरचनात्मक और क्रियात्मक कार्य करती है। प्रश्न : कोशिका की खोज किसने और कब की? उत्तर : रॉबर्ट हुक ने, सन् 1665 में। प्रश्न : जीव की मूलभूत इकाई क्या कहलाती है? उत्तर : कोशिका। प्रश्न : कोशिका के मुख्य भाग कौन-कौन से हैं? उत्तर : कोशिका झिल्ली, कोशिकाद्रव्य (साइटोप्लाज्म) और केन्द्रक। प्रश्न ...
Read more

संसाधन 8th

-
  🌟  🔶 1. संसाधन क्या हैं? (परिभाषा) हमारे आसपास मिलने वाली वे सभी चीजें जो उपयोगी हों और हमारी जरूरतें पूरी करें — संसाधन कहलाती हैं। जैसे— पानी, मिट्टी, पेड़, खनिज, मशीन, मनुष्य आदि। 🔶 2. संसाधन क्यों असमान रूप से मिलते हैं? क्योंकि हर जगह का ✔ जलवायु ✔ मिट्टी ✔ ऊँचाई ✔ तापमान अलग–अलग होता है। इसलिए संसाधन हर जगह एक जैसे नहीं होते। 🔶 3. संसाधनों के प्रमुख प्रकार (3 Types) (1) प्राकृतिक संसाधन (Nature से मिलते हैं) – उदाहरण: पानी, मिट्टी, खनिज, पेड़, जानवर – दो प्रकार: नवीकरणीय (फिर बन जाते हैं) – हवा, पानी अनवीकरणीय (जल्दी नहीं बनते) – कोयला, पेट्रोल (2) मानव निर्मित संसाधन (Man-made) – जो मनुष्य बनाता है – उदाहरण: मशीन, सड़क, इमारत, वाहन, तकनीक (3) मानव संसाधन (Human Resource) – स्वयं मनुष्य – मनुष्य का ज्ञान, कौशल, शिक्षा, क्षमता – मनुष्य प्रकृति के संसाधनों का सही उपयोग करता है। 🔶 4. जैव और अजैव संसाधन जैव (Biotic) : जीवित चीजों से — पेड़, पौधे, जानवर अजैव (Abiotic) : निर्जीव चीजें — मिट्टी, पानी, खनिज 🔶 5. वास्तविक (Actual) और ...
Read more

8th math rasiyo ki tulna

-
  Chapter 9 – राशियों की तुलना (सभी सूत्र) Chapter 9 : राशियों की तुलना (सभी सूत्र) 🔹 लाभ और हानि लाभ = विक्रय मूल्य − क्रय मूल्य हानि = क्रय मूल्य − विक्रय मूल्य लाभ प्रतिशत (%) = (लाभ × 100) / क्रय मूल्य हानि प्रतिशत (%) = (हानि × 100) / क्रय मूल्य 🔹 विक्रय मूल्य (Selling Price) विक्रय मूल्य = क्रय मूल्य + लाभ विक्रय मूल्य = क्रय मूल्य − हानि विक्रय मूल्य = क्रय मूल्य × (100 + लाभ %) / 100 विक्रय मूल्य = क्रय मूल्य × (100 − हानि %) / 100 🔹 क्रय मूल्य (Cost Price) क्रय मूल्य = विक्रय मूल्य − लाभ क्रय मूल्य = विक्रय मूल्य + हानि क्रय मूल्य = (100 × विक्रय मूल्य) / (100 + लाभ %) क्रय मूल्य = (100 × विक्रय मूल्य) / (100 − हानि %) 🔹 अंकित मूल्य और बट्टा बट्टा = अंकित मूल्य − विक्रय मूल्य बट्टा प्रतिशत = (बट्टा × 100) / अंकित मूल्य विक्रय मूल्य = अंकित मूल्य × (100 − बट्टा %) / 100 अंकित मूल्य = (100 × विक्रय मूल्य) / (100 − बट्टा %) 🔹 बिक्री कर बिक्री कर = (कर दर × अंकित मूल्य) / 100 देय राशि = अंकित मूल्य + बिक्री कर 🔹 साधारण ब्याज (...
Read more