Class 10 Science – Chapter 3
Occurrence of Metals
धातुओं की प्राकृतिक अवस्था में उपस्थिति | Minerals, Ores & Differences
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1. What are Minerals? | खनिज क्या हैं?
English:
Minerals are naturally occurring elements or compounds found in the Earth's crust.
Minerals are naturally occurring elements or compounds found in the Earth's crust.
हिंदी:
खनिज वे प्राकृतिक रूप से पाए जाने वाले तत्व या यौगिक हैं जो पृथ्वी की भूपर्पटी में पाए जाते हैं।
खनिज वे प्राकृतिक रूप से पाए जाने वाले तत्व या यौगिक हैं जो पृथ्वी की भूपर्पटी में पाए जाते हैं।
Examples of Minerals
Many metals occur in nature in the form of minerals. These minerals may contain the desired metal along with other substances.
कई धातुएँ प्रकृति में खनिजों के रूप में पाई जाती हैं। इन खनिजों में वांछित धातु के साथ अन्य पदार्थ भी उपस्थित हो सकते हैं।
Examples:
Bauxite – source of aluminium
Haematite – source of iron
Zinc blende – source of zinc
Copper pyrites – source of copper
Bauxite – source of aluminium
Haematite – source of iron
Zinc blende – source of zinc
Copper pyrites – source of copper
Important Point
Every ore is a mineral, but every mineral is not an ore.
याद रखें:
प्रत्येक अयस्क एक खनिज होता है, लेकिन प्रत्येक खनिज अयस्क नहीं होता।
प्रत्येक अयस्क एक खनिज होता है, लेकिन प्रत्येक खनिज अयस्क नहीं होता।
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2. What is an Ore? | अयस्क क्या है?
English:
An ore is a mineral from which a metal can be extracted conveniently and economically.
An ore is a mineral from which a metal can be extracted conveniently and economically.
हिंदी:
अयस्क वह खनिज है जिससे धातु को सुविधापूर्वक तथा आर्थिक रूप से लाभदायक तरीके से निकाला जा सकता है।
अयस्क वह खनिज है जिससे धातु को सुविधापूर्वक तथा आर्थिक रूप से लाभदायक तरीके से निकाला जा सकता है।
Meaning of Economically
The extraction process should not cost more than the value of the metal obtained.
धातु के निष्कर्षण की लागत, प्राप्त धातु के आर्थिक मूल्य की तुलना में उचित होनी चाहिए।
Important Examples
Iron: Haematite (Fe₂O₃)
Aluminium: Bauxite
Zinc: Zinc blende (ZnS)
Copper: Copper pyrites (CuFeS₂)
Aluminium: Bauxite
Zinc: Zinc blende (ZnS)
Copper: Copper pyrites (CuFeS₂)
Why is an ore useful?
An ore contains sufficient amount of the metal or its compound and allows extraction by practical methods.
Exam Definition:
“An ore is a mineral from which a metal can be extracted profitably or economically.”
“An ore is a mineral from which a metal can be extracted profitably or economically.”
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3. Difference Between Minerals and Ores
Minerals / खनिज
Naturally occurring substances containing metals or their compounds.
प्राकृतिक रूप से पाए जाने वाले पदार्थ जिनमें धातु या उसके यौगिक हो सकते हैं।
प्राकृतिक रूप से पाए जाने वाले पदार्थ जिनमें धातु या उसके यौगिक हो सकते हैं।
Ores / अयस्क
Minerals from which metals can be extracted conveniently and economically.
ऐसे खनिज जिनसे धातु को सुविधापूर्वक एवं आर्थिक रूप से निकाला जा सकता है।
ऐसे खनिज जिनसे धातु को सुविधापूर्वक एवं आर्थिक रूप से निकाला जा सकता है।
Key Differences
1. Meaning
Mineral is a naturally occurring substance containing a metal or its compound.
Ore is a mineral suitable for economical extraction of metal.
Mineral is a naturally occurring substance containing a metal or its compound.
Ore is a mineral suitable for economical extraction of metal.
2. Economic Value
A mineral may or may not be economically useful.
An ore is economically useful for extraction.
A mineral may or may not be economically useful.
An ore is economically useful for extraction.
3. Metal Content
A mineral may contain a low concentration of the desired metal.
An ore generally contains sufficient concentration for practical extraction.
A mineral may contain a low concentration of the desired metal.
An ore generally contains sufficient concentration for practical extraction.
4. Relationship
All ores are minerals, but all minerals are not ores.
All ores are minerals, but all minerals are not ores.
Best One-Line Answer:
All ores are minerals, but all minerals are not ores because only those minerals from which metals can be extracted economically are called ores.
All ores are minerals, but all minerals are not ores because only those minerals from which metals can be extracted economically are called ores.
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4. Occurrence of Metals | धातुओं की प्राकृतिक उपस्थिति
Metals occur in the Earth's crust either in free state or in combined state.
धातुएँ पृथ्वी की भूपर्पटी में या तो स्वतंत्र अवस्था में या संयुक्त अवस्था में पाई जाती हैं।
धातुएँ पृथ्वी की भूपर्पटी में या तो स्वतंत्र अवस्था में या संयुक्त अवस्था में पाई जाती हैं।
1. Free State / स्वतंत्र अवस्था
Less reactive metals are sometimes found in the free state because they do not readily react with other substances.
Examples: Gold, silver and platinum may occur in native/free form.
2. Combined State / संयुक्त अवस्था
Highly reactive metals are generally found in combined form as compounds such as oxides, sulphides, carbonates and halides.
Examples:
Iron – oxides such as haematite
Zinc – sulphide such as zinc blende
Copper – sulphide minerals such as copper pyrites
Iron – oxides such as haematite
Zinc – sulphide such as zinc blende
Copper – sulphide minerals such as copper pyrites
Relation with Reactivity
More Reactive Metal → Usually Combined State
Less Reactive Metal → May Occur in Free State
Important:
The occurrence of a metal in nature depends greatly on its reactivity and its tendency to form stable compounds.
The occurrence of a metal in nature depends greatly on its reactivity and its tendency to form stable compounds.
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5. Examples & Important Concepts
Important Ores
Aluminium: Bauxite
Iron: Haematite
Zinc: Zinc blende
Copper: Copper pyrites
Mercury: Cinnabar
Iron: Haematite
Zinc: Zinc blende
Copper: Copper pyrites
Mercury: Cinnabar
Mineral vs Ore – Quick Concept
Suppose a rock contains a metal compound, but the amount of metal is very small and extraction is expensive. It may be a mineral but is not considered a useful ore.
यदि किसी खनिज में धातु की मात्रा बहुत कम हो और उससे धातु निकालना महँगा हो, तो वह खनिज अयस्क के रूप में उपयोगी नहीं माना जाता।
Ore → Metal Extraction
Ore → Concentration → Extraction → Refining → Metal
The exact extraction steps depend on the reactivity and nature of the metal and its ore.
Competitive Concept
Question: Why are highly reactive metals rarely found in free state?
Answer: Highly reactive metals readily react with oxygen, water, sulphur and other substances, so they generally occur as stable compounds.
Answer: Highly reactive metals readily react with oxygen, water, sulphur and other substances, so they generally occur as stable compounds.
Question: Why can gold occur in free state?
Answer: Gold is very unreactive and therefore has a low tendency to combine with other elements.
Answer: Gold is very unreactive and therefore has a low tendency to combine with other elements.
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30 MCQs – Occurrence of Metals
1. What are minerals?
A. Only artificially prepared substances
B. Naturally occurring elements or compounds
C. Only metals
D. Only gases
Answer: B. Naturally occurring elements or compounds
Minerals occur naturally in the Earth's crust.
2. What is an ore?
A. Any rock
B. A mineral from which metal can be extracted economically
C. Pure metal only
D. A non-metal
Answer: B
3. Which statement is correct?
A. Every mineral is an ore
B. Every ore is a mineral
C. No ore is a mineral
D. Minerals and ores are identical
Answer: B. Every ore is a mineral
4. Which statement is true?
A. All minerals are ores
B. All ores are minerals but all minerals are not ores
C. No mineral is an ore
D. Ores contain no metals
Answer: B
5. Bauxite is an important ore of:
A. Iron
B. Aluminium
C. Copper
D. Zinc
Answer: B. Aluminium
6. Haematite is an important ore of:
A. Iron
B. Zinc
C. Aluminium
D. Copper
Answer: A. Iron
7. Zinc blende is an ore of:
A. Zinc
B. Iron
C. Aluminium
D. Sodium
Answer: A. Zinc
8. Copper pyrites is associated with:
A. Copper
B. Aluminium
C. Sodium
D. Calcium
Answer: A. Copper
9. Which metal may occur in free state?
A. Sodium
B. Potassium
C. Gold
D. Calcium
Answer: C. Gold
10. Highly reactive metals generally occur in:
A. Free state
B. Combined state
C. Gaseous state only
D. Liquid state only
Answer: B. Combined state
11. The occurrence of metals depends greatly on:
A. Colour only
B. Reactivity
C. Shape only
D. Density only
Answer: B. Reactivity
12. Which is a less reactive metal?
A. Sodium
B. Potassium
C. Gold
D. Calcium
Answer: C. Gold
13. An ore should allow extraction of metal:
A. At any cost
B. Economically
C. Only manually
D. Never
Answer: B. Economically
14. Which of the following is NOT generally an ore?
A. Bauxite
B. Haematite
C. Zinc blende
D. Pure water
Answer: D. Pure water
15. Cinnabar is associated with:
A. Mercury
B. Aluminium
C. Iron
D. Zinc
Answer: A. Mercury
16. Iron commonly occurs in nature in the form of:
A. Oxides
B. Noble gases
C. Pure liquid
D. Organic compounds only
Answer: A. Oxides
17. Which metal is highly reactive?
A. Gold
B. Silver
C. Potassium
D. Platinum
Answer: C. Potassium
18. Highly reactive metals form compounds readily because they:
A. Are chemically inert
B. React easily with other substances
C. Cannot lose electrons
D. Never react with oxygen
Answer: B
19. Which is an ore of aluminium?
A. Bauxite
B. Haematite
C. Cinnabar
D. Zinc blende
Answer: A. Bauxite
20. Which is an ore of iron?
A. Bauxite
B. Haematite
C. Zinc blende
D. Cinnabar
Answer: B. Haematite
21. Which is an ore of zinc?
A. Haematite
B. Bauxite
C. Zinc blende
D. Cinnabar
Answer: C. Zinc blende
22. Which is an ore of mercury?
A. Cinnabar
B. Bauxite
C. Haematite
D. Copper pyrites
Answer: A. Cinnabar
23. Which metal is least likely to be found in combined form due to very low reactivity?
A. Gold
B. Sodium
C. Potassium
D. Calcium
Answer: A. Gold
24. The major difference between mineral and ore is:
A. Colour
B. Economic feasibility of extraction
C. Physical state
D. Temperature
Answer: B
25. Which sequence is logically correct?
A. Ore → Metal extraction
B. Metal → Ore → Mineral
C. Ore → Non-metal only
D. Mineral → Always pure metal
Answer: A
26. Which metal is generally found in combined form?
A. Gold
B. Platinum
C. Sodium
D. Silver
Answer: C. Sodium
27. The main reason gold can occur in native form is its:
A. High reactivity
B. Low reactivity
C. High melting point only
D. High density only
Answer: B. Low reactivity
28. An ore generally contains:
A. No useful metal
B. Sufficient useful metal for economical extraction
C. Only water
D. Only non-metals
Answer: B
29. Which statement is scientifically most accurate?
A. All minerals are pure metals
B. All ores are minerals suitable for economical metal extraction
C. Ores contain no impurities
D. Metals occur only in free state
Answer: B
30. Which concept is most important in identifying an ore?
A. Economic extraction
B. Colour only
C. Shape only
D. Hardness only
Answer: A. Economic extraction
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30 Subjective Questions – Complete Solutions
1 Mark Questions
Q1. What is a mineral?
A mineral is a naturally occurring element or compound found in the Earth's crust.
खनिज पृथ्वी की भूपर्पटी में प्राकृतिक रूप से पाया जाने वाला तत्व या यौगिक है।
खनिज पृथ्वी की भूपर्पटी में प्राकृतिक रूप से पाया जाने वाला तत्व या यौगिक है।
Q2. What is an ore?
An ore is a mineral from which a metal can be extracted economically.
Q3. Give one example of an ore of aluminium.
Bauxite.
Q4. Name an important ore of iron.
Haematite (Fe₂O₃).
Q5. Name an ore of zinc.
Zinc blende (ZnS).
2 Mark Questions
Q6. Define mineral and ore.
Mineral: Naturally occurring substance containing a metal or its compound.
Ore: A mineral from which metal can be extracted economically.
Ore: A mineral from which metal can be extracted economically.
Q7. Why is every mineral not an ore?
Every mineral does not contain sufficient amount of the metal or may not allow economical extraction. Therefore, every mineral is not an ore.
Q8. Why are highly reactive metals generally found in combined state?
Highly reactive metals readily react with oxygen, water, sulphur and other elements. Therefore, they generally occur as stable compounds.
Q9. Why can gold occur in free state?
Gold is very less reactive and does not readily react with other elements. Therefore, it can occur in the free/native state.
Q10. State the relationship between minerals and ores.
All ores are minerals, but all minerals are not ores.
3 Mark Questions
Q11. Differentiate between minerals and ores.
Minerals: Naturally occurring substances that may contain metals or their compounds.
Ores: Minerals from which metals can be extracted conveniently and economically.
Thus, an ore is a useful mineral for metal extraction.
Ores: Minerals from which metals can be extracted conveniently and economically.
Thus, an ore is a useful mineral for metal extraction.
Q12. Explain the occurrence of metals in free and combined states.
Less reactive metals such as gold may occur in free state.
Highly reactive metals such as sodium and potassium generally occur in combined state as compounds.
The difference is mainly due to their reactivity.
Highly reactive metals such as sodium and potassium generally occur in combined state as compounds.
The difference is mainly due to their reactivity.
Q13. Give three examples of ores and their metals.
1. Bauxite → Aluminium
2. Haematite → Iron
3. Zinc blende → Zinc
2. Haematite → Iron
3. Zinc blende → Zinc
Q14. What makes a mineral an ore?
A mineral becomes an ore when the desired metal can be extracted from it conveniently and economically.
Q15. Why is economic feasibility important in defining an ore?
Metal extraction involves mining, concentration, chemical processing and refining. If the cost is too high compared with the value of the metal, the mineral is not considered a useful ore.
4 Mark Questions
Q16. Explain the difference between mineral and ore with examples.
A mineral is a naturally occurring substance containing a metal or its compound.
An ore is a mineral from which the metal can be extracted economically.
For example, bauxite is an important mineral and ore of aluminium because aluminium can be extracted from it economically.
Thus, all ores are minerals but all minerals are not ores.
An ore is a mineral from which the metal can be extracted economically.
For example, bauxite is an important mineral and ore of aluminium because aluminium can be extracted from it economically.
Thus, all ores are minerals but all minerals are not ores.
Q17. Explain why highly reactive metals are not generally found in free state.
Highly reactive metals have a strong tendency to react with other substances. They readily combine with oxygen, sulphur, water or halogens and form stable compounds.
Therefore, metals such as sodium, potassium and calcium generally occur in combined form.
Therefore, metals such as sodium, potassium and calcium generally occur in combined form.
Q18. Explain why less reactive metals can occur in free state.
Less reactive metals have little tendency to react with other substances. Therefore, they may remain uncombined in nature.
Examples include gold and platinum, which can occur in native form.
Examples include gold and platinum, which can occur in native form.
Q19. Write four important ores and the metals obtained from them.
1. Bauxite → Aluminium
2. Haematite → Iron
3. Zinc blende → Zinc
4. Cinnabar → Mercury
2. Haematite → Iron
3. Zinc blende → Zinc
4. Cinnabar → Mercury
Q20. Explain the importance of reactivity in the occurrence of metals.
The more reactive a metal is, the more readily it combines with other elements. Therefore highly reactive metals are generally found in combined form.
Less reactive metals have a lower tendency to react and may occur in free state.
Less reactive metals have a lower tendency to react and may occur in free state.
5 Mark Questions
Q21. Give a detailed explanation of minerals and ores.
Minerals are naturally occurring elements or compounds found in the Earth's crust.
They may contain useful metals along with impurities.
An ore is a mineral from which a metal can be extracted conveniently and economically.
Therefore:
Mineral: Natural substance containing metal or its compound.
Ore: Mineral suitable for economical extraction of metal.
Examples include bauxite for aluminium and haematite for iron.
They may contain useful metals along with impurities.
An ore is a mineral from which a metal can be extracted conveniently and economically.
Therefore:
Mineral: Natural substance containing metal or its compound.
Ore: Mineral suitable for economical extraction of metal.
Examples include bauxite for aluminium and haematite for iron.
Q22. Differentiate between minerals and ores on five points.
1. Definition: Mineral is a naturally occurring substance; ore is a mineral suitable for metal extraction.
2. Economic value: A mineral may not be economically useful; an ore is economically useful.
3. Metal concentration: A mineral may contain insufficient metal; an ore contains suitable concentration.
4. Extraction: Extraction from an ordinary mineral may not be economical; extraction from an ore is practical.
5. Relationship: All ores are minerals, but all minerals are not ores.
2. Economic value: A mineral may not be economically useful; an ore is economically useful.
3. Metal concentration: A mineral may contain insufficient metal; an ore contains suitable concentration.
4. Extraction: Extraction from an ordinary mineral may not be economical; extraction from an ore is practical.
5. Relationship: All ores are minerals, but all minerals are not ores.
Q23. Explain the occurrence of metals in nature with suitable examples.
Metals occur in nature in free or combined states.
Free state: Less reactive metals such as gold and platinum may occur in native form.
Combined state: Reactive metals occur as compounds such as oxides, sulphides, carbonates or halides.
Examples:
Iron – haematite
Zinc – zinc blende
Aluminium – bauxite
The form in which a metal occurs depends mainly on its reactivity.
Free state: Less reactive metals such as gold and platinum may occur in native form.
Combined state: Reactive metals occur as compounds such as oxides, sulphides, carbonates or halides.
Examples:
Iron – haematite
Zinc – zinc blende
Aluminium – bauxite
The form in which a metal occurs depends mainly on its reactivity.
Q24. Explain the meaning of economical extraction of metals.
Economical extraction means that the cost of obtaining the metal from the mineral is reasonable compared with the value of the metal obtained.
The mineral must contain sufficient useful metal and should be capable of being processed by practical methods.
Such a mineral is called an ore.
The mineral must contain sufficient useful metal and should be capable of being processed by practical methods.
Such a mineral is called an ore.
Q25. Explain the relationship among mineral, ore and metal.
A metal occurs naturally in the Earth's crust in different minerals.
Some minerals contain enough metal and allow economical extraction. These are called ores.
The ore is processed to obtain the metal.
Therefore:
Mineral → Suitable Mineral/Ore → Extraction → Metal
Some minerals contain enough metal and allow economical extraction. These are called ores.
The ore is processed to obtain the metal.
Therefore:
Mineral → Suitable Mineral/Ore → Extraction → Metal
6 Mark Questions
Q26. Explain in detail the difference between minerals and ores.
Minerals:
Minerals are naturally occurring elements or compounds found in the Earth's crust. They may contain metals in different concentrations and may contain several impurities.
Ores:
Ores are minerals from which metals can be extracted conveniently and economically.
Main differences:
1. Every ore is a mineral.
2. Every mineral is not an ore.
3. Ore must have sufficient useful metal or a suitable form for extraction.
4. Extraction from an ore must be economically feasible.
5. Ordinary minerals may not be suitable for profitable extraction.
6. Examples include bauxite for aluminium and haematite for iron.
Minerals are naturally occurring elements or compounds found in the Earth's crust. They may contain metals in different concentrations and may contain several impurities.
Ores:
Ores are minerals from which metals can be extracted conveniently and economically.
Main differences:
1. Every ore is a mineral.
2. Every mineral is not an ore.
3. Ore must have sufficient useful metal or a suitable form for extraction.
4. Extraction from an ore must be economically feasible.
5. Ordinary minerals may not be suitable for profitable extraction.
6. Examples include bauxite for aluminium and haematite for iron.
Q27. Explain how the reactivity of metals affects their occurrence in nature.
The occurrence of metals is strongly related to their chemical reactivity.
Highly reactive metals:
They readily react with oxygen, water, sulphur and halogens. Hence they are generally found in combined form.
Examples: Sodium, potassium and calcium.
Moderately reactive metals:
They generally occur as compounds such as oxides, sulphides and carbonates.
Examples: Iron, zinc and copper.
Less reactive metals:
They may occur in free/native state.
Examples: Gold and platinum.
Thus, greater reactivity generally means a greater tendency to occur in combined form.
Highly reactive metals:
They readily react with oxygen, water, sulphur and halogens. Hence they are generally found in combined form.
Examples: Sodium, potassium and calcium.
Moderately reactive metals:
They generally occur as compounds such as oxides, sulphides and carbonates.
Examples: Iron, zinc and copper.
Less reactive metals:
They may occur in free/native state.
Examples: Gold and platinum.
Thus, greater reactivity generally means a greater tendency to occur in combined form.
Q28. Explain with examples why all minerals cannot be called ores.
A mineral is a naturally occurring substance containing a metal or its compound. However, extraction of metal from every mineral is not economically feasible.
A mineral may contain a very small amount of metal, require complicated processing, or involve excessive cost.
Only those minerals from which metal can be extracted conveniently and economically are called ores.
Therefore:
All ores ⊂ Minerals
but:
All minerals ≠ Ores
A mineral may contain a very small amount of metal, require complicated processing, or involve excessive cost.
Only those minerals from which metal can be extracted conveniently and economically are called ores.
Therefore:
All ores ⊂ Minerals
but:
All minerals ≠ Ores
Q29. Write an exam-oriented note on important ores of metals.
1. Aluminium: Bauxite is the principal ore of aluminium.
2. Iron: Haematite (Fe₂O₃) is an important ore of iron.
3. Zinc: Zinc blende (ZnS) is an important ore of zinc.
4. Copper: Copper pyrites (CuFeS₂) is an important ore of copper.
5. Mercury: Cinnabar (HgS) is an important ore of mercury.
These ores are processed to extract their respective metals.
2. Iron: Haematite (Fe₂O₃) is an important ore of iron.
3. Zinc: Zinc blende (ZnS) is an important ore of zinc.
4. Copper: Copper pyrites (CuFeS₂) is an important ore of copper.
5. Mercury: Cinnabar (HgS) is an important ore of mercury.
These ores are processed to extract their respective metals.
Q30. “All ores are minerals but all minerals are not ores.” Explain this statement with examples.
Minerals are naturally occurring substances containing metals or their compounds.
When a mineral contains sufficient useful metal and the metal can be extracted conveniently and economically, the mineral is classified as an ore.
For example, bauxite is an ore of aluminium because aluminium can be extracted from it economically. Haematite is an important ore of iron.
However, a naturally occurring mineral may contain too little metal or may be too expensive to process. Such a mineral is not considered a useful ore.
Therefore, the correct conclusion is:
Every ore is a mineral, but every mineral is not an ore.
When a mineral contains sufficient useful metal and the metal can be extracted conveniently and economically, the mineral is classified as an ore.
For example, bauxite is an ore of aluminium because aluminium can be extracted from it economically. Haematite is an important ore of iron.
However, a naturally occurring mineral may contain too little metal or may be too expensive to process. Such a mineral is not considered a useful ore.
Therefore, the correct conclusion is:
Every ore is a mineral, but every mineral is not an ore.
Class 10 Science | Occurrence of Metals
Minerals + Ores + Differences + Occurrence + 30 MCQs + 30 Subjective Questions
Minerals + Ores + Differences + Occurrence + 30 MCQs + 30 Subjective Questions
