# NCERT Solutions Class 8 Science Chapter 4

## NCERT Solutions for Class 8 Science Chapter 4: Materials Metals and Nonmetals

Science subject is the study of nature and the environment, and students in Class 8 will learn about the materials, including metal and nonmetals. Materials react differently with chemicals, and it can be challenging to understand their reactions and formation. Thus, students can learn with the help of Extramarks NCERT Solutions for Class 8 Science Chapter 4 with more clarity and covers elaborative concepts.

Chapter 4, Materials Metals and Nonmetals, start with an introduction to metals and nonmetals. In addition, it talks about the physical and chemical properties of metals and nonmetals. Here, students will learn more about the role of nonmetallic elements in the environment. Further, they will get an overview of how chemicals react with different metals and nonmetals.

The NCERT Solutions for Class 8 Science Chapter 4 is available on Extramarks website. The solution helps students get a detailed overview of each  sub-topics and each concept  covered in the chapter which comprises e fill in the blanks, multiple-choice questions, match the following and true or false. Students will learn more efficiently with theory notes, illustrations,  examples, and past  years’ question papers. With regular practice, students can improve their understanding  of the topics and gain confidence in answering  advanced level questions in  Science.. The same is true for other subjects as well.

Extramarks is trusted among the students pursuing primary and secondary Classes for the best study guides and Solutions. Our Solutions for Class 8 maintain the quality by strictly following the guidelines and syllabus. It tries to develop their learning experience and provide detailed knowledge.  It will ensure that even the minutest doubt is resolved and the students develop an interest in learning and mastering the topic with ease.

Students can visit the website for the latest updates, and students can get other Class Solutions, including NCERT Solutions Class 9, NCERT Solutions Class 10, and NCERT Solutions Class 11. To enjoy the maximum benefit of these resources, students just need to register themselves at Extramarks official website and stay ahead of the pack.

## Key Topics Covered In NCERT Solutions for Class 8 Science Chapter 4

Students can take advantage of our Extramarks NCERT Solutions available in a topic-wise format to learn and understand complex concepts. The experienced Science teachers prepare the Solutions. It provides tips and tricks to score high marks in the CBSE Class 8 Science Examination. It is well explained  with illustrations and diagrams so that students can understand the concepts easily.

Introduction

Metals are those materials which are strong and have characteristic properties. It makes them ideal  for almost everything, such as iron, copper, and zinc. They are highly used in household articles, vehicles, machines, buildings, utensils etc. Besides, nonmetals are those materials that don’t have any characteristic properties such as sulphur, carbon and oxygen.

### Physical Properties of Metals and Nonmetals

• Metals possess a property that allows them to be beaten into thin sheets. This property is known as malleability. It will enable the material to change its shape and be made into thin sheets like silver foil or aluminium foil. The metals can also be drawn into wires, and this property is termed ductility. This property is known as ductility; it allows the metals like copper and converts them into cables.
• Besides, metals are good conductors of heat, and they are used for making cooking utensils, irons, heaters, etc. The metals cooperate with copper and aluminium to make electric wires and cables.
• When metals are struck hard on the surface, they make a sound effect. It is termed as being sonorous. This is due to this property that makes you hear a sound whenever you hit a metal surface. In comparison, some metals are shiny and lustrous in appearance, like gold or silver.

Key features and physical properties of metals are as follows

• Hard and have high tensile strength.
• It is a good conductor of heat and electricity.
• It has a high melting and boiling point.
• Metals are shiny silver-grey.
• They are solids at room temperature except for mercury.

The physical properties of Nonmetals discussed in NCERT Solutions for Class 8 Science Chapter 4 is as follows

• The atoms of nonmetals are smaller than those of metals.
• Nonmetals have high electronegativities, which means that the atom of nonmetals has a strong tendency. It has the capacity to  attract more electrons than it  normally would. .
• Several properties of nonmetals result from their atomic sizes.
• Nonmetals under average temperature and pressure are found as gases.
• In solid-state, nonmetals tend to be brittle and lack malleability and ductility.

### Chemical Properties of Metals and Non-metals

The chemical properties of metals are as follows:

• When they react with oxygen, metals produce basic metal oxides. Here, we can observe that the litmus paper turns red and sometimes blue, indicating a basic metal oxide formation.
• Some metals react vigorously with water, like sodium, which is kept in kerosene. It responds very slowly like iron. The metals react with water and form metal hydro-oxides and hydrogen gas.
• Metals tend to displace more reactive metals from the less reactive metals in their compounds. Here, the blue colour of litmus indicates an aqueous solution of copper sulphate and zinc disappears.
• When metals react with acids, they form metal salts and hydrogen gas. In addition, some metals like aluminium and zinc react with bases like sodium hydroxide, which helps to produce metals salts and hydrogen gas, which burns with a pop sound.

Some of the chemical properties of nonmetals are:

1. Reaction with water

A nonmetal will not react with water; however, it is usually very reactive in air. Therefore, some of them are stored in water.

For example, phosphorus is a highly reactive nonmetal, and it may catch fire when exposed to air. Thus, it is stored in water to prevent its contact with atmospheric oxygen.

1. Reaction with bases

The reaction between nonmetals and bases is complicated. When chlorine reacts with bases like sodium hydroxide gives products like sodium hypochlorite, sodium chloride, and water.

1. Reaction with acid

There are no such cases where nonmetals  reacted with acids.

1. Reaction with oxygen

When oxides react with nonmetals, their formation creates oxygen. The oxides of nonmetals are acidic or neutral.

For Example:

• When sulphur reacts with oxygen, it creates sulphur dioxide.

S + O2 → SO2

• When sulphur dioxide reacts with water, it creates sulphurous acid.

SO2 + H2O → H2SO3

### Uses of Metals and Nonmetals

Metals and nonmetals are useful  in many ways. They also contribute in  the manufacturing of equipment, machines, and aeroplanes.

Metals like gold, and silver, are used for making jewellery due to their lustrous properties.

• Copper and aluminium contribute to making wires due to their tensile properties and being good conductors of electricity.
• Mercury finds its use in the thermometers.
• Nickel and chromium are used in the electroplating and steel industry. In comparison, lead is used to manufacture batteries. Aluminium is used in packaging material as it can be rolled into sheets.
• Nonmetal like oxygen is essential for our survival and, similarly, carbon for the plants.
• Nitrogen and phosphorus are  widely used in fertilisers.
• Hydrogen is used to propel rockets, and graphite is still used for   making pencils and as lubricants in machines running at high temperature

## NCERT Solutions for Class 8 Science Chapter 4: Exercise &  Solutions

Our NCERT Solutions provide students with an in-depth knowledge of the topics with all the solved answers. The answers are comprehensive and  explained in detail such that students will rarely have any doubt after going through  the topic. Hence, it clears the doubts and also encourages s them to  learn independently without any further assistance.

Students can start their learning journey with a trial account by registering on the website. The solution guide covers all subtopics in NCERT Class 8 Science Chapter 4. It includes the chemical properties of nonmetals and the uses of metals and nonmetals. In addition, students will understand the critical effect of acid and base on metallic elements.

Students can also access the exercise specific questions and their Solutions from the repository of  study resources available at the Extramarks website, one of them  is below:

Chapter 4: Exercise 4.1 Solutions: 11 Questions

Along with this, students can also explore Extramarks NCERT Solutions for other primary and secondary Classes. Students can either visit the website, or they can also click on the links given  below:

• NCERT Solutions Class 1
• NCERT Solutions Class 2
• NCERT Solutions Class 3
• NCERT Solutions Class 4,
• NCERT Solutions Class 5
• NCERT Solutions Class 6
• NCERT Solutions Class 7
• NCERT Solutions Class 8
• NCERT Solutions Class 9
• NCERT Solutions Class 10
• NCERT Solutions Class 11
• NCERT Solutions Class 12

NCERT Exemplar for Class 8 Science

Class 8 Science is as crucial as any other subjects such as sciences and  history of our time. . There is much more than remembering formulas, theories besides why and how things function.  The subject is itself difficult to understand. NCERT exemplar contributes to developing the students’ learning ability. It helps them improve their understanding of the topics and become efficient in solving exercises with varying  levels of difficulty. By solving exemplar questions, students will be able to build a strong foundation on all concepts.

NCERT exemplars consist of different questions, including the multiple-choice question, long answer and short answer type questions. In addition, the students will witness fill in the blanks, match the following, and true or false type of questions. With regular practice of the exemplar, students can expect a good score in the examination. In other words, effort has been made to ensure that nothing is left in the process.

Extramarks NCERT Solutions for Class 8 Science Chapter 4 provides examples from exemplars that cover metals and nonmetals. Students will enhance their understanding of  multiple topics such as physical properties and chemical properties of metals & nonmetals and ensure to get their best score.

## Key Features of NCERT Solutions for Class 8 Science Chapter 4

Extramarks has  an in-house  team of subject experts dedicated to preparing appropriate Solutions for  each topic and each section covered in the chapter. The solution guide helps students grasp the concepts discussed in the chapter. It will ensure that even the minutest doubt is resolved and the students develop an interest in learning and mastering the topic with ease.

Some of the characteristics and features of NCERT Solutions for Class 8 Science Chapter 4 are as follows:

• Every type of metal and nonmetal is explained  with  proper illustrations.
• The Solutions are designed to help the students to get a deeper understanding of the physical properties of metals.
• Every concept  is well elaborated by using good examples so that students can remember them during the exam.
• Students will  learn how to define  chemical properties of metals and non-metals.
• The subject matter experts prepare NCERT Solutions for Class 8 Science Chapter 4 while adhering to the CBSE guidelines and curriculum.

Q.1 Which of the following can be beaten into sheets?
(a) Zinc
(b) Phosphorous
(c) Sulphur
(d) Oxygen

Ans. Correct option is (a) Zinc.
Explanation: Generally metals can be beaten into sheets. Zinc is a metal while phosphorus, sulphur and oxygen are non-metals.

Q.2 Which of the following statements is correct?
(a) All metals are ductile.
(b) All non-metals are ductile.
(c) Generally, metals are ductile.
(d) Some non-metals are ductile.

Ans. Correct statement is option (c), Generally, metals are ductile.
Explanation: Mercury is a metal but it cannot be drawn into wires because it is liquid at room temperature. Therefore, it is non-ductile.

Q.3 Fill in the blanks.
(a) Phosphorous is a very ___________ non-metal.
(b) Metals are ________ conductors of heat and __________.
(c) Iron is ________reactive than copper.
(d) Metals react with acids to produce ________ gas.

Ans.

(a) reactive
(b) good, electricity
(c) more
(d) hydrogen

Q.4 Mark ‘T’ if the statement is true and ‘F’ if it is false.
(a) Generally, non-metals react with acids. ( )
(b) Sodium is a very reactive metal. ( )
(c) Copper displaces zinc from zinc sulphate solution. ( )
(d) Coal can be drawn into wires. ( )

Ans.

(a) Generally, non-metals react with acids. (F)
(b) Sodium is a very reactive metal. (T)
(c) Copper displaces zinc from zinc sulphate solution. (F)
(d) Coal can be drawn into wires. (F)

Q.5 Some properties are listed in the following table. Distinguish between metals and non-metals on the basis of these properties.

 Properties Metals Non-metals Appearance Hardness Malleability Ductility Heat Conduction Conduction of Electricity

Ans.

 Properties Metals Non-metals Appearance Lustrous Non-lustrous Hardness Hard Soft Malleability Can be beaten into thin sheets Cannot be beaten into thin sheets Ductility Can be drawn into wires Cannot be drawn into wires Heat Conduction Good conductors of heat Poor conductors of heat Conduction of Electricity Good conductors of electricity Poor conductors of electricity

Q.6 Give reasons for the following.
(a) Aluminium foils are used to wrap food items.
(b) Immersion rods for heating liquids are made up of metallic substances.
(c) Copper cannot displace zinc from its salt solution.
(d) Sodium and potassium are stored in kerosene.

Ans.

(a) Aluminium is a highly malleable cheap metal which does not react with food items. Therefore, aluminium foils are used to wrap food items.
(b) Metals are good conductors of heat and electricity. Therefore, immersion rods used for heating liquids are made up of metallic substances.
(c) A less reactive metal cannot replace more reactive metal from its salt solution. Since, copper is less reactive than zinc, therefore, it cannot replace zinc from its salt solution.
(d) Sodium and potassium are very reactive metals. They react vigorously with oxygen and water. A lot of heat is generated in the reaction. If kept in open, they react with oxygen and moisture present in air and catch fire immediately. Therefore, sodium and potassium are stored in kerosene.

Q.7 Can you store lemon pickle in an aluminium utensil? Explain.

Ans. No, lemon pickle cannot be stored in an aluminium utensil. This is because lemon pickle contains acid which reacts with aluminium (metal) to liberate hydrogen gas. The liberated hydrogen gas can spoil lemon pickle.

Q.8 Match the substances given in column A with their uses given in column B.

 A B (i) Gold (a) Thermometers (ii) Iron (b) Electric wire (iii) Aluminium (c) Wrapping food (iv) Carbon (d) Jewellery (v) Copper (e) Machinery (vi) Mercury (f) Fuel

Ans.

 A B (i) Gold (d) Jewellery (ii) Iron (e) Machinery (iii) Aluminium (c) Wrapping food (iv) Carbon (f) Fuel (v) Copper (b) Electric wire (vi) Mercury (a) Thermometers

Q.9 What happens when

(a) Dilute sulphuric acid is poured on a copper plate?

(b) Iron nails are placed in copper sulphate solution?

Write word equations of the reactions involved.

Ans.

(a) When sulphuric acid is poured on a copper plate, the copper metal reacts with sulphuric acid to form copper sulphate and hydrogen gas.

(b) Iron is more reactive than copper therefore, it displaces copper from copper sulphate solution to form iron sulphate.

Initially, copper sulpahte solution is blue in colour. when iron nail is placed in it, the blue colour of copper sulphate solution fades. The solution turns green due to formation of iron sulphate. Copper gets deposited on iron nail.

Q.10 Saloni took a piece of burning charcoal and collected the gas evolved in a test tube.

(a) How will she find the nature of the gas?

(b) Write down word equations of all the reactions taking place in this process.

Ans.

(a) To find the nature of the gas, add a small amount of water into the test tube in which gas is collected. Quickly cover the test tube and shake it well. Now test the solution with red and blue litmus paper one by one. You will observe that solution turns blue litmus red while red litmus remains unaffected. This confirms that gas evolved during burning of charcoal is acidic in nature.

(b) Name of the product formed in the reaction of charcoal with oxygen is carbon dioxide.

$\begin{array}{l}C\text{ }+\text{ }{O}_{2}\text{ }\stackrel{}{\to }\text{ }C{O}_{2}\\ Carbon\text{ }Oxygen\text{ }Carbon\text{ }dioxide\\ \left(from\text{ }\phantom{\rule{0ex}{0ex}}charcoal\right)\end{array}$

When carbon dioxide is dissolved in water, carbonic acid is formed. The carbonic acid turns blue litmus paper red. Generally, oxides of non-metals are acidic in nature.

$\begin{array}{l}C{O}_{2}\text{ }+\text{ }{H}_{2}O\text{ }\stackrel{\text{ }\stackrel{}{}}{\to }\text{ }{H}_{2}C{O}_{3}\\ Carbon\text{ }\\ dioxide\text{ }Water\text{ }Carbonic\text{ }acid\\ \text{ }\left(Turns\text{ }blue\text{ }litmus\text{ }red\right)\end{array}$

Q.11 One day Reeta went to a jeweller’s shop with her mother. Her mother gave an old gold jewellery to the goldsmith to polish. Next day, when they brought the jewellery back, they found that there was a slight loss in its weight. Can you suggest a reason for the loss in weight?

Ans. To polish gold jewellery, it is dipped in a mixture of acids called aqua regia (a mixture of hydrochloric acid and nitric acid). The outer layer of gold jewellery dissolves in the acid mixture and the inner shiny layer appears. Due to dissolution of upper layer of gold, its weight gets reduced.

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##### FAQs (Frequently Asked Questions)
1. What is the difference between a metal and a nonmetal?

Metal is described as chemical elements that lose valence electrons to form positive ions. On the other hand, nonmetals are those elements that do not exhibit  properties of metals.

2. What uses of nonmetals are given in Class 8 Science Chapter 4 solution?

Nonmetals are used in fertilisers and create essential elements like Liquid hydrogen, a nonmetal used to propel rockets, and graphite used in pencils.

3. What are the essential topics for Class 8 Science Chapter 4?

The physical and chemical properties of metals and nonmetals are highlighted in this chapter. Further, it also elaborates on the uses of metals and nonmetals.