Metals (2)

CENTRAL BOARD OF SECONDARY EDUCATIONShiksha Kendra, 2, Community Centre, Preet Vihar, Delhi-110 092 India

CBSE-i

CLASS

VIIIUNIT-5

ChemistryMETALS AND NON-METALS

TEACHER’S MANUAL

Teachers’ Manualon

Metals and

non-MetalsClass VIII • UnIt 5

Central Board of SeCondary eduCationShikSha kendra, 2 Community Centre, Preet Vihar, delhi–110092

T he CBSE-International is grateful for permission to reproduce and/or translate copyright material

used in this publication. The acknowledgements have been included wherever appropriate and sources from where the material may be taken are duly mentioned. In case any thing has been missed out, the Board will be pleased to rectify the error at the earliest possible opportunity.

All Rights of these documents are reserved. No part of this publication may be reproduced, printed or transmitted in any form without the prior permission of the CBSE-i. This material is meant for the use of schools who are a part of the CBSE-International only.

vUnit 5: Metals and Non-metals

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E ducation plays the most important role in acquiring professional and social skills and a positive attitude to face the challenges

of life.Curriculum is a comprehensive plan of any educational programme. It is also one of the means of bringing about qualitative improvement in an educational system. The Curriculum initiated by Central Board of Secondary Education-International (CBSE-i) is a progressive step in making the educational content responsive to global needs. It signifies the emergence of a fresh thought process in imparting a curriculum which would restore the independence of the learner to pursue the learning process in harmony with the existing personal, social and cultural ethos.

The CBSE introduced the CBSE-i curriculum as a pilot project in few schools situated outside India in 2010 in classes I and IX and extended the programme to classes II, VI and X in the session 2011-12. It is going to be introduced in classes III, VII and for Senior Secondary classes with class XI in the session 2012-13.

The Senior Secondary stage of education decides the course of life of any student. At this stage it becomes extremely important for students to develop the right attitude, a willingness to learn and an understanding of the world around them to be able to take right decisions for their future. The senior secondary curriculum is expected to provide necessary base for the growth of knowledge and skills and thereby enhance a student’s potential to face the challenges of global competitiveness. The CBSE-i Senior Secondary Curriculum aims at developing desired professional, managerial and communication skills as per the requirement of the world of work. CBSE-i is for the current session offering curriculum in ten subjects i.e. Physics, Chemistry, Biology, Accountancy, Business-Studies, Economics, Geography, ICT, English, Mathematics I and Mathematics II. Mathematics at two levels caters to the differing needs of students of pure sciences or commerce.

viUnit 5: Metals and Non-metals

The Curriculum has been designed to nurture multiple intelligences like linguistic or verbal intelligence, logical-mathematical intelligence, spatial intelligence, sports intelligence, musical intelligence, inter-personal intelligence and intra-personal intelligence.

The Core skills are the most significant aspects of a learner's holistic growth and learning curve. The objective of this part of the core of curriculum is to scaffold the learning experiences and to relate tacit knowledge with formal knowledge. This involves trans-disciplinary linkages that would form the core of the learning process. Perspectives, SEWA (Social Empowerment through Work and Action), Life Skills and Research would be the constituents of this 'Core'.

The CBSE-i Curriculum evolves by building on learning experiences inside the classroom over a period of time. The Board while addressing the issues of empowerment with the help of the schools' administering this system strongly recommends that practicing teachers become skilful and lifelong learners and also transfer their learning experiences to their peers through the interactive platforms provided by the Board.

The success of this curriculum depends upon its effective implementation and it is expected that the teachers will make efforts to create better facilities, develop linkages with the world of work and foster conducive environment as per recommendations made in the curriculum document.

I appreciate the effort of Dr. Sadhana Parashar, Director (Training), CBSE, Dr. Srijata Das, Education Officer, CBSE and their teams involved in the development of this document.

The CBSE-i website enables all stakeholders to participate in this initiative through the discussion forums. Any further suggestions on improving the portal are always welcome.

Vineet Joshi

Chairman, CBSE

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Unit 5: Metals and Non-metalsvii

AdvisoryShri Vineet Joshi, Chairman, CBSEDr. Sadhana Parashar, Director (Academics & Training), CBSE

Conceptual FrameworkShri G. Balasubramanian, Former Director (Acad), CBSEMs. Abha Adams, Consultant, Step-by-Step School, Noida Dr. Sadhana Parashar, Director (Academics & Training), CBSE

Ideators VI-VIII

Ms. Aditi MishraMs. Avanita Bir Ms. Deepa PuriMs. Himani Asija Mr. Maneesh JaryalMs. Preeti Hans Ms. Sonali Sinha Ms. Uma Sharma

Ms. Anuradha JoshiMs. Charu Maini Dr. G.P. BagoriaMr. Manish Jaryat Ms. Neera Chopra Dr. Rajesh HassijaMs. Sudha RaviDr. Usha Sharma

Mr. Albert Abraham Prof. Chand Kiran Saluja Ms. Gayatri Khanna Ms. Mallika Preman Ms. Neelima SharmaMs. Rita BokilMs. Sunita TanwarMs. Vijay Laxmi Raman

Ms. Asha Sharma Ms. Deepa Shukla Ms. Guneet OhriMs. Monika Mehan Ms. Neerada SureshMs. Seema Rawat Ms. Urmila Guliani

Material Production Groups: Classes VI-VIIIEnglish:Ms. Dipinder KaurMs. Gayatri KhannaMs. Neerada SureshMs. Neha SharmaMs. Preeti HansMs. Rachna PanditMs. Renu AnandMs. Ritu BadiaVashisthMs. Sarita AhujaMs. Sheena ChhabraMs. Sudha RaviMs. Trishya MukherjeeMs. Veena BhasinMs. Vijay Laxmi Raman

Core-ResearchMs. Anita SharmaMs. Gayatri KhannaDr. K L ChopraMs. Manjushtha BoseMs. Neha SharmaMs. Neeta RastogiDr. N K SehgalMs. Rashmi KathuriaMs. Renu AnandMs. Varsha Manku

Chemistry:Ms. Kavita KapoorMs. Poonam Kumar MendirattaMs. Rashmi Sharma

Physics:Ms. Mukta KaushikMs. Patarlekha SarkarMs. Vidhu Narayanan

Biology:Ms. Deepti SharmaMs. Deepa ShuklaMs. Monika Munjal GandhiMs. Sarika AttriMs. Varsha ParikhMs. Yamini Bisht

Economics:Mr. A. ManoharanMs. Anita YadavMs. Leela Garewal

Core-PerspectivesMs. Madhuchhanda, Ms. Neha Sharma

Theatre and Performing Arts:Ms. Asha SinghMs. Amrita Shiv KumarMs. Archana SharmaMs. Bindia RajpalMs. Deepti SharmaMs. Manisha GoelMs. Priya SrinivasanMs. Shruti Sharma

Mathematics:Ms. Chhavi RahejaMs. Deepa GuptaMs. Gayatri ChowhanMr. Mahendra ShankarMs. Mamta GoyalMs. N VidyaDr. Ram AvtarMr. Rahul Sofat

Hindi:Mr. Akshay Kumar DixitMs. Kiran SoniMs. Nishi DhanjalMs. Veena Sharma

Core-Sewa:Ms. Neha SharmaMs. Nishtha BharatiMs. Reema AroraMs. Seema BhandariMs. Seema ChopraMs. Vandna

ICT:Ms. Babita MahajanMs. Chanchal ChandnaMs. Purvi SrivastavaMs. Ritu AroraMs. Swati PanhaniMs. Shally AroraMs. Sameeksha Mishra

Geography:Ms. Aditi BabbarMs. Mallika Preman Ms. Neena PhogatMs. Nisheeth KumarMs. Suparna SharmaMs. Sharda HansMs. Sushila PandeyMs. Sunita BajpaiMs. Tundra Reddy

History:Ms. Dalia HaldarMs. Dolly HaryalMs Kalpana PantMs Leeza DuttaMs. Nasreen RekhangeMs. N. SarojMs. Navita GaylaMs. Ruchi MahajanMs. YachanaVillaitrari

Political Science:Ms. Kanu ChopraMs. Manisha AnthwalMs. Mamta TalwarMs. Rashmi MishraMs. Saudamini TipraMs. Shilpi Anand

Visual Arts:Ms. Anjali AnandMs. Minakshi Ms. Rani BhatnagarMs. Renu Gupta Mr. Subroto Mallick

Chief Co-ordinator: Kshipra Verma, EOCo-ordinators

(Late) Dr. Srijata Das E.OShri R. P. Sharma Consultant (Science)Mr. Navin Maini RO (Tech)

Ms. Neha SharmaD.D.Ms. Neelima Sharma, Consultant (English)Shri Al Hilal AhmedAEO

Ms. S. Radha MahalakshmiE. O.Ms. Reema Arora, Consultant (Chemistry)Mr. R P Singh, AEO

Ms. P RajeswaryE.O.Ms. Deepa Shukla, Consultant (Biology)Mr. Sanjay Sachdeva D. O.

Acknowledgements

viiiUnit 5: Metals and Non-metals

Syllabus Coverage ................................................................. ix

Learning Outcomes ................................................................ x

Lesson Plan Matrix ............................................................... xi

Cross-Curricular Links .......................................................xiii

Teacher Notes ...................................................................... 1–8

Summary .................................................................................. 9

Student Worksheets .............................................................. 10

Additional Reference Links ................................................ 18

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ixUnit 5: Metals and Non-metals

5.1 Introduction to Metals and Non-metals

5.2 Position of Metals and Non-metals in the Periodic Table

5.3 Physical Properties of Metals and Non-metals

5.4 Chemical Properties of Metals and Non-metals

5.5 Reactivity Series

5.6 Displacement Reactions

5.7 Corrosion

5.8 Prevention of Corrosion

Syllabus Coverage

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Unit 5: Metals and Non-metalsx

At the end of this unit, students would be able to:

u Understand the position of metals and non-metals in the periodic table. (brief layout)

u Study the physical properties of metals and non-metals highlighting the exceptions.

u Identify the substances around you as metals and non-metals.

u Differentiate between the physical properties of metals and non-metals.

u Investigate the effect of air, water, acids and bases on metals and non-metals and compare the properties.

u Recall the burning of magnesium ribbon in air and identify the nature of the oxide formed by using litmus solution.

u Perform an activity to show the liberation of Hydrogen gas on reaction of zinc metal with dilute hydrochloric acid.

u Define displacement reactions.

u Study the reactivity of different metals (for example: zinc and Copper) with the salt solution (Ferrous sulphate).

u Introduction to the terms minerals and ores.

u Recognise the uses of metals and non-metals in day to day life.

u Investigate the factors causing corrosion in metals.

Suggested Activities

u Visit the jewellery shop to observe the ductile nature of gold and silver.

u Perform an experiment to arrange the given metals (Iron, copper, aluminum, zinc) in decreasing order of reactivity using displacement reactions.

u Collect pictures/ information of various metals depicting their uses and make a collage. (Group activity).

u Perform an experiment to determine the conditions under which corrosion takes place.

Learning Outcomes

Unit 5: Metals and Non-metalsxi

Content Expected Learning Outcomes Skills

Warm-up Activity Through the introductory activity students will learn the classification of elements as metals and non-metals.

• Classifying• Inference drawing

5.1. Introduction: Recapitulate the structure of atom and extra space around the nucleus. Students will get aware of the common substances in our daily life.

• Learning by doing

5.2. Position of metals and non-metals in the Periodic table

Students will get familiar with the periodic table. Moreover, they will also get an idea about different types of elements.

• Observing • Interpreting

5.3. Physical properties of metals and non-metals

Understand the physical properties of metals and non-metals.Learn the various exceptions to these properties.Student Activity 1Student Activity 2Student Activity 3Student Activity 4Student Activity 5Student Activity 6

• Understanding• Learning by doing• Comparing

5.4. Chemical Properties of metals and non-metals

Learn the periodic pattern in the periodic table. Student Activity 7Student Activity 8Student Activity 9Student Activity 10Student Activity 11Student Activity 12

• Learning by doing• Interpreting

Lesson Plan Matrix

Unit 5: Metals and Non-metalsxii

5.5. Reactivity Series Compare the reactivity of metals and non-metals under given reaction conditions.Student Activity 13Student Activity 14

• Interpreting

5.6. Displacement Reactions

Discuss the conditions under which the displacement reactions occur.

• Difference between less reactive and more reactive metals gets clear.

5.7. and 5.8. Corrosion and Prevention of corrosion

Discuss in the class can be carried regarding corrosion and its preventive measures.Student Activity 15

• General awareness

Unit 5: Metals and Non-metalsxiii

u English: Students will learn the meaning of new terms and develop the skill of writing project report of various reactions of metals and non-metals with various reagents.

u ICT: Computers knowledge will help the students to make:

v Power point presentations.

v Research work done by the students to perform various activities.

v Learning through knowledge based videos.

u Physics: Knowldege of Physics helps the students to investigate and classify substances as good or poor conductor of electricity and heat.

u Biology: The students will be able to appreciate the presence of iron metal in haemoglobin and magnesium metal in chlorophyll.

Cross Curricular Links

5.1 Introduction

Metals and non-metals is a unit which is introduced in the class to develop the broad classification of elements as metals and non-metals. It gives them insight for the combination of elements to form compounds and makes them competent for the writing of electronic configuration of elements. It also highlights the important physical and chemical properties shown by the metals and non-metals. The unit demonstrates the reason for the vanishing of lustre possessed by the metals with time i.e. Corrosion. This develops the aesthetic sense of the students as they explore the varied applications of metals and non-metals in our daily life.

Warm up Activity

The Teacher is suggested to introduce the unit by warm up activity in the class. Herein, few of suggestive introduction activities are given which may be taken up in the class:

The curiosity in the minds of students can be developed by asking them to relate the presence of the metals in the coins. [Teacher may show different coin images]

OR

The concept can also be introduced in the class by asking the students to recall Bronze age or Iron age. [This relates to Science unit of class 6].

ORThe conceptual idea of metals can also be given by asking them few straight questions like:

Why the bells in church and temples are made up of iron or brass and not of wood?

Teachers’ Notes

Unit 5: Metals and Non-metals2

Why the jewellery made up of gold don’t lose its shiny appearance?

Can a cotton yarn be used for the conduction of electricity rather than aluminium or copper wires?

Diamond has a shiny appearance. Is it a metal or non-metal?

OR

Teacher can also ask them to recall matter and its classification as elements, compounds and mixture.

From here the teacher will be formally introducing the sub classification of elements as metals and non-metals.

5.2 Position of Metals and Non-metals in The Periodic Table

The teacher may show them the periodic table and ask them to name few known elements. Simultaneously, teacher can depict their position with the help of a pointer on the periodic table.

Source: elementsdatabase.com


The teacher may define the periodic table as:

‘The tabular display of elements in which they are placed on the basis of their properties is known as a Periodic Table.’

Teacher can broadly classify elements electronically in a tabular fashion as:

• Metals

• Non-metals and

• Metalloids

Now, the teacher may explain about the existence of elements in the free state as well as in the combined state in the nature. ‘free state’ means that the element has not combined with any other element to form compound whereas in the combined state the element has combined with other elements to form compounds. For comparison, Teacher may give example of elements existing in free state (such as gold) which cannot combine with other elements while example of elements existing in combine state (such as aluminium) can be discussed in the class. ‘Bauxite’ is the combined state of aluminium metal.

The electronic concept of atom can then be given by showing them the model of an atom. An analogy of planetary system can be given here where nucleus is taken equivalent to the Sun whereas planets will be taken equivalent to the electrons, revolving around the nucleus in their defined path. Then students are given the reason for the combination of elements to complete duplet or octet of electrons to acquire stability.

Students must be given enough practice for writing of electronic configuration and practice. They should be made competent enough to calculate the number of valence electrons so that concept of valency can be related.

Occurence of Metals and Non-metals in Nature

The idea of existence of metals and non-metals in the minds of students can be kindled by narrating them the existence of gold from the time before writing of even history. Bronze age and Iron Age actually describe the artmanship of man to play with the metals. Generally, the metals which exist in nature in the free state are used to make jewellery. From the very beginning Gold has been associated with jewellery and sculpture because of its malleability and existence in the very pure state in nature. A country’s wealth is estimated by the amount of gold it possesses. It is a symbol of wealth today as well.


Copper is a metal which exist in the free state as well as in the combined state. After discussing this, the teacher may discuss about the minerals, ores and gangue.

In combined state metals exist with many impurities and these compounds are called minerals.

The minerals from which metal can be extracted conveniently and profitably are called ore.

Hence all ores are minerals but all minerals are not ores.

The process of extraction of metals from their ores is called Metallurgy.

The teacher may ask them to explore and write the chemical formulae of the ores of the metals and apply their knowledge of first module to write their chemical names in the tabular form as

METAL ORE CHEMICAL FORMULAE CHEMICAL NAME

Iron Haemetite Fe2O3 Iron Oxide

Similarly, the concept of non-metals in the free as well as combined state can be extended in the class.

5.3 Physical Properties of Metals and Non-metals

In class 8, it is very important for the teacher to explain very clearly the meaning of the terms physical and chemical properties to the students. After explaining the meaning, the teacher may take up one by one all the physical properties to discuss as per the Student Manual. For example, teacher may discuss Student Activity 1 in the class and ask the students to classify all the substances into two categories namely shiny and dull.

Web resources may be shared by the Teacher in the class according to specific requirements.

Notes


SUBSTANCE SHINy DULL

gold

sulphur

charcoal

aluminium

At the end, teacher may conclude and discuss the activity performed.

Metals have shiny appearance and non-metals do not. The teacher must bring to the notice of the students that Iodine though is a non-metal, it is lustrous. Further, the teacher may discuss the reason for this.

Similarly rest of the properties may be discussed with the help of Student Activities 2, 3, 4 and 5. For the property of malleability, teacher can either take the students to see Jeweller’s work man ship or teacher can himself beat the piece of metal with the help of hammer and can explain the property of malleability. The idea can be extended to show the brittleness of charcoal or wood. While giving this demonstration to the students, the teacher must take care that the students should not hurt themselves with the hammer.

Then teacher must discuss the safety rules before carrying out any activity in the class.

To explain the concept of conductivity, the teacher must elicit the meaning of this term from the students only and then she should classify the conductivity as:

(i) Thermal Conductivity i.e. conduction of heat.

(ii) Electrical conductivity i.e. conduction of electric current. To elaborate the meaning of the term electrical conductivity, the teacher must ask the students as per the figure to arrange the circuit. The teacher can further ask them to test various materials provided to them and write a project report to comment on the electrical conductivity of these materials.

For the concept of electrical conductivity, the teacher can demonstrate Student Activity 7 in the class. For this the material required can be purchased from a

Source: www.goalfinder.com/


local hardware shop. It is advisable to paint each square in black so that both the blocks should look alike and moreover black colour increases the thermal conductivity. Teacher may give brief introduction about thermal conductivity and then extend this idea by sorting the periodic table on the basis of thermal conductivity.

Student Activity 1

Aim: To study the thermal conductivity of a metal and a non-metal.

Material Required: Steel bars and pieces of plywood cut in to 3 inch square block which should be painted black.

Steps: • Paint the blocks in black colour and allow them to be completely

dry.

• Ask a student to touch the blocks from the back side of their hand.

• Feel it carefully.

• Place a ice cube on both the blocks and observe it carefully.

1. Which of the given block feels colder?

………………………………………………………………………………

2. Which of the given block allows the ice to melt faster?

………………………………………………………………………………

Metal block feels colder because it conducts heat from our hand much faster than the wooden block as wooden block is made up of carbon which is a non-metal.

The teacher must make the students appreciate that both the blocks are in the same environment so they are at the same temperature, but one feels colder than the other because the metal block has a much higher heat capacity than the wooden block and it conducts heat away from our hand much faster than the wooden block. Metal block supply heat at a much faster rate than wooden block to the ice and hence ice melts at a very slow rate on the wooden block which appears warmer to us.


The teacher may also share with the students that steel has thermal conductivity 100 times more than the wood. The experiment can also be performed by taking the blocks made up of aluminium and plywood. (as aluminium has thermal conductivity 15 times more than the plywood)

The teacher may ask the students to explore various other combinations which can be used to perform this activity.

5.4 Chemical Properties of Metals and Non-metals

The teacher must emphasise the exceptions present in the physical properties of the elements so that the students should be brought to the level that they should be able to understand that the physical properties cannot be the sole criterion for this classification of elements. From here the teacher will formally introduce the concept of chemical properties.

5.4.1 Reaction with OxygenBefore showing this activity to the students, the teacher must discuss the safety rules to the students. He must ensure that the students are wearing the proper lab coat and safety glasses as Magnesium burns with a dazzling flame. After this the teacher may demonstrate Student Activity 8 and 9 to the class and emphasize that

Metals react with oxygen to form the respective metal oxides which are basic in nature.

Example: 4 Na + O2 2Na2O

4K + O2 2K2O

4Al + 3O2 2Al2O3

Some metals like sodium or potassium are so reactive that the moment they come in contact with air, they catch fire. Hence, they are stored in kerosene to prevent this contact.

Some of the metal oxides dissolve in water to form metal hydroxides which are basic in nature.

The teacher must help the students to recall module “acids and bases” of class 7 to check the nature of oxide.


Likewise, students can be asked to predict that non-metals form oxide with oxygen which is acidic in nature.

Non-Metals react with oxygen to form the respective non-metallic oxides.

Example: S + O2 SO2

C + O2 CO2

The solution of the non-metallic oxides in water is generally acidic in nature. SO2 + H2O H2SO3

CO2 + H2O H2CO3

While performing this activity the teacher must explain to the students that they should not inhale the vapours of SO2 or CO2 as they can be choking.

5.4.2 Reaction with Water

To explain this chemical property, the teacher may take any metal, as per the Student Activity 10, sodium has to be used. The teacher must discuss about the sodium metal with the students and the counted number of pieces of fennel sized should be placed in the china dish duly dipped in kerosene.

Student Activity 11 and 12 may be taken up as an additional activity. Other, reaction with acids may be discussed in the class through Student Activity 13 and 14.

5.5 and 5.6 Reactivity Series and Displacement Ractions

In this section, teacher may discuss about the speed of reactivity of metals and non-metals (Table 5.1 given in the Student Manual demonstrates the same). This will help to develop an understanding in the students about the ease with which different metals can be extracted. In addition, displacement reaction can be taken up through Student Activity 15.

5.7 and 5.8 Corrosion and Prevention of Corrosion

Teacher may explain the process of corrosion and its prevention here. Research Project will help in developing better understanding of the same.


u Metals have lustrous property while non-metals do not have such property.

u Generally, metals are ductile, good conductor of electricity while non-metals are not.

u Metals burn with oxygen and produce oxides while Non-metals produce non-metallic oxides.

u Non-metals do not react with water while a metal reacts to form hydroxides.

u Metals react with acids while non-Metals do not.

u More reactive metals displace less reactive metals in aqueous solutions.

u Metals corrodes while the corrosion can also be prevented under certain conditions.

u Metals and non-metals have wide applications in daily life.

Summary


A. Check what you have learnt:

1. Name three metals which are lustrous.

…………………………………………………………………………………

2. Name a metal which is found in the liquid state.

…………………………………………………………………………………

3. Name a non metal which is found in the liquid state.

…………………………………………………………………………………

4. Name a nonmetal which is used to make electrode in the cells.

…………………………………………………………………………………

5. Name a metal which is used to make aircraft bodies.

…………………………………………………………………………………

6. Name a metal whose very thin layer is used to cover space shuttles and satellites.

…………………………………………………………………………………

7. Name a metal which is used to make cans of cold-drinks.

…………………………………………………………………………………

8. Name a non-metal which is purple coloured solid, lusturous, soluble in carbon tetrachloride.

…………………………………………………………………………………

9. Name a non-metal which is essential for life.

…………………………………………………………………………………

10. Name a non-metal which is yellow coloured solid, insoluble in water but soluble in carbon disulphide.

…………………………………………………………………………………

S t u d e n t W o r k S h e e t 1


A. 1. sodium. Copper, aluminium

2. Mercury

3. Bromine

4. Carbon

5. Aluminium

6. Gold

7. Tin

8. Iodine

9. Oxygen

10. Sulphur

B. Element A is a metal as it is solid, conducts electricity and malleable as well

B. Vishakha found four elements namely, A, B, C and D. She carried out various tests on these elements and noted down the results as depicted in the table:

S.NO ELEMENT SOLID AT ROOM TEMPERATURE

CONDUCTS ELECTRICITy

OR NOT?

MALLEABLE

1 A Yes Yes Yes

2 B Yes Yes No

3 C Yes No No

4 D No No No

Help Vishakha to analyze these results and locate the metal out of these four elements.

A n S W e r



1. Complete the following flow chart by taking an example and writing the chemical symbols and formulae of the reactants and the products.

ELEMENTS

METALS

Neutralization reaction

NON-METALS

Reacts with water to form basic oxide

Reacts with water to form acidic oxide

Basic oxides dissolve in water tom form alkali

Acidic oxides combine with water to form acids

2. Name the following: (a) The oxide formed when nonmetals react with oxygen. (b) The gas produced when metals react with acids. (c) The gas which burns with a pop sound. (d) The compound formed when metals react with sulphuric acid. (e) The gas produced when metal reacts with water.


3. Write the appropriate stoichiometric coefficient and complete the following balanced equation:

(a) Na + H2O (b) K + H2O

(c) Ca + H2O (d) Zn + HCl

(e) Ca + H2SO4 (f) Mg + H2O

4. All the fizzy drink contain carbonic acid dissolved in it. For its preparation carbon has to be burnt in the sufficient supply of oxygen to form carbon- di-oxide. When the water is poured into a beaker containing carbon dioxide and is shaken well, carbon dioxide dissolve in water partially.

(a) Give the chemical formula of the product formed. (b) What will be the effect of the product on the blue litmus solution? (c) Write the balanced equation for the above reaction.

5. Explain the difference in observation. (a) When Sam puts zinc piece into hydrochloric acid. (b) When Sam puts sulphur into hydrochloric acid.

6. Devansh wants to prepare magnesium oxide from its elements. It is a reaction between:

(a) A metal and a non metal (b) Two metals (c) Two non metals (d) An acid and a base

7. Which of the following reactions is feasible? Give reasons for your answer.

(a) Fe + H2 SO4 FeSO4 + H2 (b) Cu + H2 SO4 CuSO4 + H2

8. Write the chemical equations for the following: (a) Aluminium is kept in dilute hydrochloric acid . (b) Sodium is kept in air for sometime. (c) Boiled water is poured on magnesium metal.

9. An element ‘X’ reacts with oxygen to form an oxide with formula ‘X2O’. The oxide is soluble in water and turns red litmus to blue. Identify whether X is a metal or a non-metal.

10. A metal X is found in the form of filings which are attracted by a magnet. These filings react with steam and dilute hydrochloric acid to evolve hydrogen gas. X also reacts with sulphur to form a compound which is not attracted by a magnet. Identify X. Also write the chemical equation for its reaction with hydrochloric acid.


2. (a) Acidic oxide (b) Hydrogen (c) Hydrogen (d) Metal sulphate (e) Hydrogen

3. (a) 2Na + H2O Na2O + H2 (b) 2K + H2O K2O +H2

(c) Ca +H2O CaO + H2 (d) Zn +2 HCl ZnCl2 + H2

(e) Ca + H2SO4 CaSO4 +H2 (f) Mg + H2O MgO +H2

A n S W e r

ELEMENTS

METALS Na

Neutralization reactionNaOH +H2CO3 Na2CO3 +H2O

NON-METALS C

Reacts with water to form basic oxide

Na + H2O Na2O +H2

Reacts with water to form acidic oxide C + O2 CO2

Basic oxides dissolve in water tom form alkali

Na2O + H2O NaOH

Acidic oxides combine with water to form acidsCO2 + H2O H2CO3


4. (a) H2CO3

(b) Changes to red.

(c) CO2 + H2O H2CO3

5. Zn will react with HCl to produce Hydrogen gas whereas sulphur being the nonmetal will not react with acid

6. (a) A metal and a non metal.

7. (a) is feasible as copper being less reactive than hydrogen will not displace hydrogen.

8. (a) 2Al + 6HCl 2AlCl3 + 3H2

(b) 4Na + O2 2Na2O

(c) Mg + 2H2O Mg(OH)2 + H2

9. Metal as metals form basic oxides.

10. X is Iron metal Fe + HCl FeCl2 + H2



1. A copper coin is kept immersed in silver nitrate solution for some time. What change will be observed and why? Also mention the change observed.

2. Sunaina had three metals X, Y and Z. She wanted to arrange them in order of their reactivity. For this she carried out some chemical tests and observed the following reactions:

XCl3 + Y YCl3 + X

ZO + Y Y2O3 + Z

ZSO4 + X X2SO4 + Z

On the basis of above chemical equations answer the following questions:

(a) Which of the three metals is the most reactive? (b) Which of the three metals is the least reactive? (c) Arrange the three metals in order of their reactivity.

3. Complete the following chemical equations: (a) Fe + CuCl2 (b) Zn + Fe2O3 (c) Mg + AgNO3 (d) Cu + AgNO3

4. Can we store ferrous sulphate solution in zinc container? Give reasons for your answer. Write the chemical equation involved.

1. Copper displaces silver as it is more reactive. A bleu coloured solution will be formed and grey coloured solid will be deposited at the bottom of the container.

2. (a) Y (b) Z (c) Z< X < Y

3. (a) Fe + CuCl2 FeCl2 + Cu (b) 3Zn + Fe2O3 3ZnO + 2Fe (c) Mg + 2AgNO3 Mg(NO3)2 + 2Ag (d) Cu + 2AgNO3 Cu(NO3)2 + 2Ag

4. No as zinc displaces iron Zn + FeSO4 ZnSO4 + Fe

A n S W e r



1. A museum wants to enrich its cultural heritage. They hired few archeologists who while digging at a site found shiny bright gold pendent, a reddish brown iron sword which was chipped from the sides and a black colored silver bracelet. Explain these observations.

2. Give two reasons, why aluminium cans are used to keep cold drinks?

3. Shaina bought a silver necklace for herself. After a few days she observed a black coating on the necklace. She was surprised to see the coating. Explain the reason for the colour change. What is the composition of the black layer developed on silver?

4. Why are iron articles galvanized?

5. Why is corrosion of aluminium advantageous?

1. It indicates that gold does not corrode, iron gets rusted and a layer of Fe2O3.xH2O is formed. Silver also get corroded and a layer of black Ag2S is formed on its surface

2. They are light weight, Resistant to corrosion, Recyclable

3. Silver undergoes corrosion.

Composition of the layer is silver sulphide

4. To prevent rusting of iron

5. It prevents the metal from further oxidation

A n S W e r


Additional Reference Links

u http://hyperphysics.phy-astr.gsu.edu/hbase/pertab/metal.html

u www.ausetute.com.au/nonmetals.html

u www.intechopen.com/books/upcoming/subject/metals-and-nonmetals

u www.articlesnatch.com/Article/The-Reactivity-Series/4134438

u www.cambridge.org/9780521578479


CBSE-iCENTRAL BOARD OF SECONDARY EDUCATION

Shiksha Kendra, 2, Community Centre, Preet Vihar, Delhi-110 092 India

Metals (2)

Science

neerada suresh

renu anand

gayatri khanna

preeti hans

mallika preman

deepti sharma

neha sharma

deepa shukla