CBSE Class 8 Science Exemplar Chapter 4: Materials - Metals and Non-Metals NCERT Solutions

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NCERT Solutions PDF Class 8 PDF

This chapter delves into the fundamental properties of materials, distinguishing between metals and non-metals. The NCERT Solutions for Class 8 Science Exemplar, Chapter 4, provide clear explanations and step-by-step answers to various questions. Students will learn to identify metals and non-metals based on their physical characteristics like malleability, ductility, and state at room temperature. The solutions also cover their reactivity with acids and help in understanding why certain materials exhibit specific behaviors. These solutions are designed to reinforce learning and aid in effective exam preparation by clarifying complex concepts related to the classification of elements.

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Quick info

BoardCBSE
ClassClass 8
SubjectScience Exemplar
Session2026
LanguageEnglish
TypeNCERT Solutions
ChapterChapter 4

Chapter summary

Chapter 4 of the Class 8 Science Exemplar focuses on the classification of elements into metals and non-metals. The NCERT Solutions cover key properties such as malleability, ductility, sonority, and conductivity, along with exceptions like sodium and mercury. It also touches upon the reaction of metals with acids. These solutions offer a comprehensive review of the chapter's core concepts, helping students solidify their understanding of material properties.

Learning outcomes

  • Identify metals and non-metals based on their physical properties.
  • Understand the concepts of malleability and ductility.
  • Recognize exceptions to general properties of metals (e.g., sodium, mercury).
  • Differentiate between metals and non-metals through their reactions.
  • Solve problems related to the classification of elements.

Topics covered

Paper topics

  • Metals
  • Non-metals
  • Malleability
  • Ductility
  • Properties of metals
  • Properties of non-metals
  • Exceptions to metal properties
  • Reactions with acids

Important topics

  • Distinguishing Metals and Non-metals
  • Malleability and Ductility
  • Exceptions: Sodium and Mercury
  • Reactivity with Acids

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Questions and Solutions

Multiple Choice Questions - 1

1. Which of the following is not a metal?
  1. copper
  2. sulphur
  3. aluminium
  4. iron
Solution: The correct option is (b) sulphur. Sulphur is a non-metal, while copper, aluminium, and iron are metals. Metals typically exhibit properties like conductivity, malleability, and ductility, which non-metals generally do not possess.

Multiple Choice Questions - 2

2. Which of the following substances will be flattened into a thin sheet when beaten with a hammer?
  1. crystal of iodine
  2. lump of sulphur
  3. piece of coal
  4. zinc granule
Solution: The correct option is (d) zinc granule. Metals possess the property of malleability, which allows them to be beaten into thin sheets without breaking. Non-metals, such as iodine, sulphur, and coal, are brittle and tend to break into pieces when hammered.

Multiple Choice Questions - 3

3. Boojho has learned that non-metals on beating with a hammer are generally broken into pieces. Which of the following is a non-metal?
  1. iron nail
  2. aluminium wire
  3. copper plate
  4. piece of coal
Solution: The correct option is (d) piece of coal. Iron, aluminium, and copper are metals, which are typically malleable and can be shaped by hammering. Coal, on the other hand, is a non-metal and is brittle, breaking into pieces when subjected to force.

Multiple Choice Questions - 4

4. Materials which can be drawn into wires are called ductile. Which of the following is not a ductile material?
  1. silver
  2. copper
  3. sulphur
  4. aluminium
Solution: The correct option is (c) sulphur. Ductility is a characteristic property of metals, allowing them to be drawn into wires. Sulphur is a non-metal and does not possess this property.

Multiple Choice Questions - 5

5. Metals are generally hard. Which of the following metals is an exception and can be cut with a knife?
  1. iron
  2. sodium
  3. gold
  4. magnesium
Solution: The correct option is (b) sodium. While most metals are hard, sodium is a notable exception. It is a soft metal that can be easily cut into pieces using a knife due to its low density and metallic bonding structure.

Multiple Choice Questions - 6

6. Metals are generally solid. Which of the following metals is in the liquid state at room temperature?
  1. mercury
  2. silver
  3. aluminium
  4. sodium
Solution: The correct option is (a) mercury. Mercury is a unique metal that exists in a liquid state at standard room temperature and pressure. Silver, aluminium, and sodium are all solid metals under these conditions.

Multiple Choice Questions - 7

7. Metals generally react with dilute acids to produce hydrogen gas. Which one of the following metals does not react with dilute hydrochloric acid?
  1. magnesium
  2. aluminium
  3. iron
  4. copper
Solution: The correct option is (d) copper. Metals like magnesium, aluminium, and iron are more reactive than hydrogen and will displace it from dilute acids like hydrochloric acid, producing hydrogen gas. Copper is less reactive than hydrogen and therefore does not react with dilute hydrochloric acid to produce hydrogen gas.

Common mistakes

  • Confusing properties of metals with non-metals.
  • Forgetting exceptions to general properties (e.g., softness of sodium, liquid state of mercury).
  • Incorrectly classifying materials based on limited information.

Revision tips

  • Create a table summarizing the properties of metals and non-metals, including exceptions.
  • Practice identifying metals and non-metals from given descriptions or examples.
  • Review the explanations for each question to understand the reasoning behind the answers.
  • Focus on understanding the 'why' behind each property and classification.

Practice MCQs

Q1. Which of the following substances is classified as a non-metal?

Q2. Which material, when beaten with a hammer, will flatten into a sheet, indicating it is a metal?

Q3. Which of the following is a non-metal that breaks into pieces when hammered?

Q4. Which of the following materials is NOT ductile, meaning it cannot be easily drawn into wires?

Q5. Which of the following metals is an exception to the general property of hardness and can be cut with a knife?

Q6. Which of the following metals is typically found in a liquid state at room temperature?

Frequently asked questions

What is the main focus of Chapter 4, Materials: Metals and Non-Metals for Class 8 Science?

Chapter 4 focuses on differentiating between metals and non-metals based on their physical and chemical properties, including malleability, ductility, and reactivity.

What are the key properties of metals discussed in these NCERT Solutions?

The solutions discuss properties like being malleable (can be beaten into sheets), ductile (can be drawn into wires), generally hard, and good conductors of heat and electricity. Exceptions are also highlighted.

Which metals are mentioned as exceptions to the general properties?

Sodium is mentioned as an exception because it is soft enough to be cut with a knife, and Mercury is an exception as it is a liquid at room temperature.

How do these NCERT Solutions help in exam preparation?

These solutions provide clear, step-by-step explanations for each question, helping students understand the concepts thoroughly and reinforcing their knowledge for exams.

What is the difference between malleability and ductility?

Malleability is the ability of a metal to be hammered or pressed into thin sheets without breaking, while ductility is the ability to be drawn out into a thin wire.

Important links

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