Chemistry Standard X Part 1 PDF

CHEMISTRY Standard X Part 1 NT-487-1-CHEMISTRY-10-E-VOL.1 Government of Kerala De...

CHEMISTRY Standard X Part 1 NT-487-1-CHEMISTRY-10-E-VOL.1 Government of Kerala Department of General Education State Council of Educational Research and Training (SCERT) Kerala 2019  THE NATIONAL ANTHEM Jana-gana-mana adhinayaka jaya he Bharatha-bhagya-vidhata, Punjab-Sindh-Gujarat-Maratha Dravida-Utkala-Banga Vindhya-Himachala-Yamuna-Ganga Uchchala-Jaladhi-taranga Tava subha name jage, Tava subha asisa mage, Gahe tava jaya gatha. Jana-gana-mangala-dayaka jaya he Bharatha-bhagya-vidhata, Jaya he, jaya he, jaya he, Jaya jaya jaya jaya he! PLEDGE India is my country. All Indians are my brothers and sisters. I love my country, and I am proud of its rich and varied heritage. I shall always strive to be worthy of it. I shall give my parents, teachers and all elders respect, and treat everyone with courtesy. To my country and my people, I pledge my devotion. In their well-being and prosperity alone lies my happiness. State Council of Educational Research and Training (SCERT) Poojappura, Thiruvananthapuram 695012, Kerala Website : www.scertkerala.gov.in, e-mail : [email protected] Phone : 0471 - 2341883, Fax : 0471 - 2341869 Typesetting and Layout : SCERT Printed at : KBPS, Kakkanad, Kochi-30 © Department of General Education, Government of Kerala 1234567890123456 1234567890123456 1234567890123456 1234567890123456 1234567890123456 Dear children, 1234567890123456 1234567890123456 1234567890123456 1234567890123456 1234567890123456 1234567890123456 Scientific activity, while enabling social progress, must also 1234567890123456 1234567890123456 1234567890123456 1234567890123456 uphold eco-friendly values. This should happen at deeper levels 1234567890123456 1234567890123456 of any science enquiry and activity. The text has tried to 1234567890123456 1234567890123456 1234567890123456 1234567890123456 1234567890123456 1234567890123456 incorporate such ideologies to the possible extent and to discuss 1234567890123456 1234567890123456 1234567890123456 1234567890123456 emerging areas like Green Chemistry. 1234567890123456 1234567890123456 1234567890123456 1234567890123456 1234567890123456 1234567890123456 The text provides opportunities for student's active 1234567890123456 1234567890123456 1234567890123456 1234567890123456 participation in the classrooms. We have tried to organise these 1234567890123456 1234567890123456 1234567890123456 1234567890123456 activities giving due emphasis to the level of your competence 1234567890123456 1234567890123456 1234567890123456 through investigative learning. 1234567890123456 1234567890123456 1234567890123456 1234567890123456 1234567890123456 1234567890123456 The initial units focus on explaining peculiarities of elements 1234567890123456 1234567890123456 1234567890123456 1234567890123456 related to their electronic configuration, identifying the 1234567890123456 1234567890123456 1234567890123456 1234567890123456 1234567890123456 relationship between mass of substances and their number of 1234567890123456 1234567890123456 1234567890123456 1234567890123456 molecules and also identifying the significance of mole concept 1234567890123456 1234567890123456 1234567890123456 in chemistry. Following this, discussions on the rate of reactions 1234567890123456 1234567890123456 1234567890123456 1234567890123456 1234567890123456 and equilibrium and chemical reactivity of metals and their 1234567890123456 1234567890123456 1234567890123456 1234567890123456 stages of production are made. Some basic concepts in Organic 1234567890123456 1234567890123456 1234567890123456 1234567890123456 Chemistry are discussed in this textbook. 1234567890123456 1234567890123456 1234567890123456 1234567890123456 1234567890123456 1234567890123456 The educational portal ‘Samagra’ and the QR Code 1234567890123456 1234567890123456 1234567890123456 1234567890123456 incorporated textbook make the classroom learning process 1234567890123456 1234567890123456 1234567890123456 1234567890123456 effortless and stimulating. National Skills Qualification 1234567890123456 1234567890123456 1234567890123456 1234567890123456 Framework (NSQF), Disaster management techniques relevant 1234567890123456 1234567890123456 1234567890123456 1234567890123456 to contemporary issues and the ICT possibilities are considered 1234567890123456 1234567890123456 1234567890123456 1234567890123456 1234567890123456 in this textbook. 1234567890123456 1234567890123456 1234567890123456 It is the duty of each one of you to assimilate ideas in this 1234567890123456 1234567890123456 1234567890123456 1234567890123456 1234567890123456 1234567890123456 text, carry out the activities effectively and attain your goal. 1234567890123456 1234567890123456 Hope that your journey be fruitful in this through active 1234567890123456 1234567890123456 1234567890123456 1234567890123456 1234567890123456 1234567890123456 interactions and appropriate activities. 1234567890123456 1234567890123456 1234567890123456 1234567890123456 1234567890123456 1234567890123456 Wishing you the best... 1234567890123456 1234567890123456 1234567890123456 1234567890123456 1234567890123456 Dr J. Prasad Director, SCERT  CONSTITUTION OF INDIA Part IV A FUNDAMENTAL DUTIES OF CITIZENS FUNDAMENTAL ARTICLE 51 A Fundamental Duties- It shall be the duty of every citizen of India: (a) to abide by the Constitution and respect its ideals and institutions, the National Flag and the National Anthem; (b) to cherish and follow the noble ideals which inspired our national struggle for freedom; (c) to uphold and protect the sovereignty, unity and integrity of India; (d) to defend the country and render national service when called upon to do so; (e) to promote harmony and the spirit of common brotherhood amongst all the people of India transcending religious, linguistic and regional or sectional diversities; to renounce practices derogatory to the dignity of women; (f) to value and preserve the rich heritage of our composite culture; (g) to protect and improve the natural environment including forests, lakes, rivers, wild life and to have compassion for living creatures; (h) to develop the scientific temper, humanism and the spirit of inquiry and reform; (i) to safeguard public property and to abjure violence; (j) to strive towards excellence in all spheres of individual and collective activity so that the nation constantly rises to higher levels of endeavour and achievements; (k) who is a parent or guardian to provide opportunities for education to his child or, as the case may be, ward between age of six and fourteen years. 1 PERIODIC TABLE AND ELECTRONIC CONFIGURATION....................... 07 2 GAS LAWS AND MOLE CONCEPT................ 32 3 REACTIVITYSERIES AND ELECTROCHEMISTRY...................................... 47 4 PRODUCTION OF METALS............................. 62 THE SYMBOLS USED IN THE TEXTBOOK Additional Information (Need not be assessed) ICT Possibilities for Concept Clarity Let Us Assess Extended Activities  Is there an atom model, other than Bohr's? Are there shells inside shells? The secrets inside an atom are unending... You may have the same curiosity as that of the child when you have read about the structure of the atom. The scientific community has developed the concepts about an atom through many experiments and assumptions. You know that the periodic table, in which there is a comprehensive classification of elements, is based on atomic structure. What is the basis of classification of elements in the periodic table? Chemistry $ Standard - X If you know the atomic number of an element, you can determine its position and nature from the periodic table. Subshells Eg: Atomic number of sodium is 11. The names s, p, d, f are given to Electronic configuration -    subshells based on words indicating Group number -.............................. certain properties related to the atomic spectra of elements. s → Period number -.............................. sharp, p → principal, d → diffuse, f • Is this group 1 element a metal or → fundamental. a non - metal? According to modern theories of atomic structure, electrons revolve in a three dimensional region The classification in this table is done in such a around the nucleus. Each main way that we can analyse and predict the energy level has sublevels or properties of elements. In the periodic table, the subshells. In these subshells, there basis of the periodic function of elements is their are regions where there is a high atomic structure. Let’s see how the latest probability of finding electrons. knowledge about an atom and periodic table are These are known as orbitals. The related. maximum number of electrons that can be accommodated in an orbital You have learnt about various atom models. is 2. The s subshell has only one According to Bohr model, in an atom electrons orbital with a spherical shape. The are arranged in various shells around the nucleus p subshell has 3 orbitals which are and they are filled in the increasing order of dumb-bell shaped, the d subshell energy. has 5 orbitals and the f subshell has As the distance from the nucleus increases, 7 orbitals. The shapes of these the energy of the electrons in the shells orbitals are more complex. increases and the attractive force between the nucleus and the electrons decreases. The electronic configuration of lithium (Li) is 2, 1. Like this, write the electronic configuration of sodium and argon and complete Table 1.1. Element Shells   s subshell 11 18  p subshell Table 1.1 8  Periodic Table and Electronic Configuration $ How many electrons are present in the M shell, the outermost shell of argon? $ What is the maximum number of electrons that can be accommodated in the M shell? Potassium (K), the element next to argon has one electron more than that of argon. The electronic configuration of potassium is 2, 8, 8, 1. Why does the last electron of potassium go to the 4 shell instead of occupying the third shell, even though the third shell has the capacity to accommodate ten more electrons? You have seen the anxiety expressed by the child given in the introductory picture? You have also learned that the studies related to the atomic structure are progressing continuously. Bohr model is a simple explanation of the atomic structure. Studies related to the nature and position of the electrons in an atom revealed the limitations of the Bohr model and new assumptions were postulated. Accordingly electrons in each energy level are arranged in its sub energy levels. Each sub Using the KALZIUM energy level in a shell is called a subshell. They are named as s, software of IT @ school Edubuntu, p, d, f respectively. Each main energy level except ‘K’ has more check the accuracy of than one subshell. The number of subshells in each energy level the entries in Table is equal to its shell number. 1.1. The ‘K’ shell, which is the first shell, has 1 subshell. The next ‘L’ shell has 2, and so on. • What will be the number of subshells in the ‘M’ shell and ‘N’ shell?      See the subshells present in each shell shown in Table 1.2. Shell number     Subshells     Table 1.2 Which subshell is common to all shells? 9 Chemistry $ Standard - X How can you identify the shell in which each subshell belongs to? Let’s give the serial number of the shell to the symbol of the sub shell. For example, ‘ls’ to indicate the ‘s’ subshell of the first shell and ‘2s’ for the ‘s’ subshell of the second shell and so on. Complete the Table 1.3.        s s p s p d s p d f   ! ! 1s - - - 3p - - - 4d - Table 1.3 The number of electrons in subshells Haven’t you found out from the table which all subshells are present in each shell? You know the maximum number of electrons that can be accommodated in each shell. Then, how many electrons can be accommodated in each subshell? On the basis of your discussion points, complete the Table 1.4 given below. Shell number 1 2 3 4           2 8 18 32           1s 2s 2p 3s 3p 3d 4s 4p 4d 4f -           2 2 - - - - - - - -           Table 1.4 What is the maximum number of electrons that can be accommodated in the ‘s’ subshell? Among the 8 electrons in the second shell, 2 will be in the ‘s’ sub shell. What may be the maximum number of electrons to be filled in the ‘p’ subshell? Find out by completing the table. 10  Periodic Table and Electronic Configuration You have seen the maximum number of electrons that can be accommodated in the ‘s’ and ‘p’ shells. Fill the columns regarding the third shell and find out the maximum number of electrons that can be accommodated in the ‘d’ subshell? Likewise, find out by filling the table, how the 32 electrons in the fourth shell are distributed in s, p, d, f subshells? The maximum number of electrons that can be accommodated in each sub shell is given in Table 1.5. Filling of electrons in sub shells Subshell s p d f "   !  $ %  #!   #   ##!!  Table 1.5 Filling of electrons in the subshell The electrons are filled in shells in the increasing order of their energy. For example the electronic configuration of carbon (C) is 2, 4. The first two electrons are filled in the ‘K’ shell, which has the lowest energy and the remaining four electrons are filled in the ‘L’ shell which has higher energy. Likewise, when the electrons in an atom are distributed in subshells, they are filled in the increasing order of the energies of subshells. This is called subshell electronic configuration. Then what will be the subshell wise electronic configuration of the carbon atom? Let’s familiarise on how to write the subshell wise electronic configuration of elements. The number of electrons in an atom is equal to its atomic number (Z). The atomic number of hydrogen is 1 (H). How many electrons are present? In which shell is the electron filled? In which subshell? The subshell electronic configuration of hydrogen can be represented as 1s. 1s (Read it as one s one) How many electrons are present in helium (He)? 11 Chemistry $ Standard - X Complete the subshell electronic configuration. ....... Let’s see the way of writing the electronic configuration of the next element lithium (Li). Of the total 3 electrons, if 2 electrons are filled in 1s, then the remaining electron should enter the 2s subshell as it comes next, in the order of the increasing energy. How many electrons are filled in 2s? 2...... Read the electronic configuration of lithium as one s two, two s one (1s, 2s). Complete the electronic configuration of beryllium. $ &'()*...... ...... The next element is boron, isn’t it? After filling 1s & 2s the next higher energy level is 2p. Write the electronic configuration of boron. $ &'(+)*22......... $ Write the electronic configuration of carbon. ,'($)*........................... When we write the subshell wise electronic configuration, the number on the left side of the subshell denotes the shell number and the number on the top right side denotes the number of electrons. Write down the subshell electronic configuration of the elements given below and complete the Table 1.6. Element No. of electrons Subshell electronic configuration 7 - 223 9. / ........................... 11 * ........................... ......... 13  * ........................... ......... ......... 17 , * * 18  * * Table 1.6 12  Periodic Table and Electronic Configuration                        
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   †‰††          Figure 1.2 13 Chemistry $ Standard - X Electrons are filled in the subshells of scandium in the order 2 2 6 2 6 2 1 But this is written as 1s 2s 2p 3s 3p 3d 4s, ie., in the order of the shells. Based on the increasing order of energy, once the 4s is filled, the next electron should go to 3d. This is how Sc gets the electronic configuration 2, 8, 9, 2. $ Write the electronic configuration of  Ti,  V, the two elements after Sc. Let us familiarise another method of representing subshell electronic configuration. While writing the subshell electronic configuration of elements with higher atomic numbers, the symbol of the noble gas preceding that element may be shown within square brackets followed by the electronic configuration of the remaining subshells. The electronic configuration of potassium is 1s 2s 2p 3s 3p 4s. The preceding noble gas argon has the electronic configuration 1s 2s 2p 3s 3p. Hence we may write the configuration of potassium using the symbol of argon as given below. ' ) 1 Which is the noble gas preceding sodium 111 23 Write its subshell electronic configuration. 10  Subshell electronic configuration of sodium. 11  - - - - 14  Periodic Table and Electronic Configuration Using the symbol of neon, write down the subshell electronic configuration of sodium. Find out the preceding noble gas with the help of the periodic table and complete Table 1.7. Elements Subshell electronic configuration 21 # ' ) 1 2 Using the KALZIUM 20 , software of IT @ School Edubuntu 12 4 check the accuracy of the activity in Table 27 ,! 1.7. 30 ( Table 1.7 Peculiarity of the electronic configuration of chromium (Cr) and copper (Cu) $ Write the subshell electronic configuration of  Cr. $ The stable electronic configuration of Cr is 2 2 62 6 5 1. Analyse and find out the reason for this from the box given below. The d sub shell can accommodate a maximum of 10 electrons. The completely filled configuration (d ) or the half filled configuration (d ) of this subshell is more stable than the others. Based on this, atoms with d s, d s configurations will have some changes in the filling of electrons to attain stability. Likewise, for f sub shell, f and f arrangements are more stable. On the basis of this, identify the correct electronic configuration of Cu from those given below: • 1s2 2s2 2p6 3s2 3p6 3d9 4s2 • 1s2 2s2 2p6 3s2 3p6 3d10 4s1 15 Chemistry $ Standard - X For the subshell electronic configurations of chromium and copper, the configurations with half filled d subshell or completely filled d subshell show greater stability. o If the subshell wise electronic configuration of an atom is 2 262, find answers to the following: How many shells are present in this atom? Which are the subshells of each shell? Which is the subshell to which the last electron was added? What is the total number of electrons in the atom? What is its atomic number? How can the subshell electronic configuration be written in short form? Subshell electronic configuration and blocks Use the KALZIUM software of IT @ Based on the subshell electronic configuration, elements are School Edubuntu for classified into four blocks s, p, d and f in the modern periodic further clarification. table. The periodic table, with the blocks labelled, is given in Figure 1.3. Analyse it and complete Table 1.8. s block p block        d block Nh Mc Ts Og f block Figure 1.3 16  Periodic Table and Electronic Configuration Element Atomic Subshell The subshell to Block Number electronic which the last configuration electron is added 3  12 4 7 21 # Table 1.8 Which is the subshell of lithium to which the last electron was added? What about the subshell to which the last electron of nitrogen Using the KALZIUM was added? software of IT @ School Edubuntu check the accuracy of What is the relation between the subshell to which the last the activity in Table electron was added and the block to which the element 1.8. belongs to? Write the subshell electronic configurations of the following elements and find the blocks to which they belong. a. 4 Be b. 26 Fe c. 18 Ar The block to which the element belongs will be the same as the subshell to which the last electron is added. In the periodic table, elements in groups 1 & 2 belong to s block, those in groups 13 to 18 belong to the p block and those in groups 3 to 12 belong to the d block. The elements in the f block are placed at the bottom of the periodic table in two separate rows. The period and the group can be found out on the basis of subshell electronic configuration. You know how to find the period number of an element on the basis of its shell wise electronic configuration. Let us see how to find the period from subshell electronic configuration. Complete Table 1.9. 17 Chemistry $ Standard - X Element Subshell No. of the outer most Period electronic configuration shell number 4 & 2 2   6 , 2 2 2   11 2 2 6 1  * 2 2 6 2 6 1 19        * * Table 1.9 The period number is same as the shell number of the outer most shell in the subshell electronic configuration. The group number of s block elements The group number of elements can be found on the basis of subshell electronic configuration. Some elements are given in Table 1.10. With the help of the periodic table (Figure 1.4) complete the table. Element Subshell electronic No. of electrons Group configuration present in the number last subshell  2 1   2 2 6 1 *  4 2 2 6 2 *  , 2 2 6 2 6 2 * * Table 1.10 It is clear that the elements in groups 1 and 2 belong to s block. $ What is the relation between number of electrons present in the last s subshell and their group number?.!!#5!#! !! 6 4! 18  Periodic Table Hints Atomic number Gases Symbol Name in English Liquids (Name in Latin/Greek) Artificial Elements -71 -Lu -Lr Nh Mc Ts Og Nihonium Moscovium Tennessine Oganesson 57 La 2,8,18,18,9,2 89 Ac 2,8,18,32,18,9,2. 4 1.4 As per IUPAC recommendations Lanthanum (57La) in a Lanthanoid and Actinium (89Ac) in an Actinoid 19 Periodic Table and Electronic Configuration Chemistry $ Standard - X Some common characteristics of 's' block elements You have learned that the s block elements contain alkali metals and alkaline earth metals. Their oxides and hydroxides are basic in nature. When the s block elements react, do they donate or accept electrons? Which type of chemical bond is usually formed? Ionic bond/Covalent bond We can understand that s block elements usually form ionic compounds. How many electrons are donated by the first group elements in chemical reactions? What about the second group elements? $ Suppose that 1 and 2 group elements are represented by the symbols X and Y. Complete the table given below. Group Valency Oxidation state Symbol of Chemical formula ions of oxides st4! '7)  8 * 729 nd 4! ':)  * :2+ * Table 1.11 Upon completing the table, it can be seen that ‘s’ block elements show definite valency and oxidation state. ‘s’ block elements are present at the extreme left side of the periodic table. Relating to their position, what other characteristics can be listed out? 20  Periodic Table and Electronic Configuration More metallic character Less ionisation energy Less electronegativity $ $ List out the characteristics of s block elements and prepare a note. p block elements $ Which are the groups included in the p block. Look at the portion of the second period of p block elements in the periodic table. Group Number       " !  " #          $ %  ! &2 &'1 &2 &'2 &2 &'3 &2 &'4 &2 &'5 &2 &'6 Table  $ In which subshell did the filling of the last electron take place? 1 to 6 electrons are seen in the p subshell. p block starts in the periodic table after 12 groups. Can you find out the group number by adding 12 to the number of p electrons? Analyse with respect to the given table. Element No. of p electrons Group Number 5 &  8    7 *  8   10  *  8    Table 1.13 The outermost subshell wise electronic configuration of an element Y (Symbol is not real) is 2 4. 21 Chemistry $ Standard - X To which period and group does this element belong to? Write down the outermost subshell electronic configuration of the element coming just below it in the same group. These can be written due to the similarity in the electronic configuration of these elements. Characteristics of p block elements See the portion of the periodic table which contains the p block elements. p-$    + $ - Metals Non - metals Metalloids Noble gases Nh Mc Ts Og Figure # As evident from the figure, elements representing different classes are included in this picture. Elements in the solid, liquid and gaseous states at room temperature are also included in this block. Find out examples of elements in such different states with the help of the periodic table (Fig. 1.4). p block elements usually show higher ionisation energy than the s block elements. Which element has the highest ionisation energy in each period? Think on the basis of electronic configuration. 22  Periodic Table and Electronic Configuration The element having the highest electronegativity is in the p block. Find its name and position. Analyze the general characteristics of the p block elements and prepare a note on this. Complete the Table 1.14, (X, Y) are not real symbols. Outermost Complete subshell Atomic Element electronic electronic number Period Group Block configuration configuration Z 7  2 :  2 5 Table  Which element has a valency 1? Which element shows metallic character? Which element has the highest ionisation energy? Write the chemical formula of the compound formed by the combination of X and Y and label the oxidation states. d block elements Where is the position of d block elements in the periodic table? From which period onwards does the d block begin? The d block elements in the fourth period are given in the table below. The electronic configuration of the last two subshells, 3d and 4s are given in the table. Group 3 4 5 6 7 8 9 10 11 12     + $ -  / % Element # ; < , . ,! , (  1 2    3 2 2 2  5 1   2 5  6 2  7 2  8 2  10 1  10 2 Table # 23 Chemistry $ Standard - X Is there any relationship between group number and the total number of electrons present in the 3d and 4s sub shells? Examine. The group number of the d block elements will be the same as the sum of electrons in the outermost s subshell and the number of electrons in the preceding d subshell. Characteristics of d block elements The elements Zn, Cd, Hg d block elements are those in which the last electron is which belong to the 12 filled in the d subshell of the penultimate shell. They group do not show the are also known as transition elements. common characteristics Put a tick mark 'ü' against the statements given below of transition elements. which are applicable to d block elements. Hence they are known as pseudo transition elements. These are metals. The last electron is filled in the penultimate shell. In the case of these elements in the 4  period, the last electron is filled in 4s. These are found in groups 3 to 12 of the periodic table. You have already learned that representative elements which belongs to s and p groups show similarity in their respective groups. This is because the elements of the same group have the same number of electrons in the outermost shells. Analyse the electronic configuration of the 3d and 4s subshells of the d block elements in the 4 period which are given in Table 1.15. What is the speciality in the number of electrons present in the outermost 4s subshell? Do transition elements show similarity in periods? Likewise, it can be inferred that there will be similarity in the outermost electronic configuration in succeeding periods 24  Periodic Table and Electronic Configuration as well. Write the subshell electronic configuration of the element which comes just below scandium. 4d 5s The outermost subshell electronic configuration of the transition elements are generally the same in a group and also along a period. Therefore they show similarities in properties not only in groups but also in periods. Oxidation state of d block elements You know that valancy is the number of electrons lost or gained or shared by atoms during chemical bond formation. The concept of oxidation state is also known to you. Look at the names and chemical formulae of two different chlorides of iron (Fe) given below. o Ferrous chloride þ.,2 o Ferric chloride þ.,3 The oxidation state of chlorine is (–1). Find the oxidation state of Fe in these compounds and then complete Table 1.16. Compound Oxidation state Symbol of Fe ions of Fe.,2.,3 Table % When d block elements undergo chemical reactions, along with the electrons in the outermost subshell, the electrons in the penultimate d subshell also take part. In the d block elements, electrons are not lost in the same order as they are filled up, that is electrons are lost from the outermost s subshell first. Look at the sub shell electronic configuration of Fe. 2 262 6 6 2 How does Fe change to Fe? 25 Chemistry $ Standard - X Write down the subshell electronic configuration of Fe. In FeCl, iron loses 3 electrons to form Fe ion. There is only a small difference of energy between the outermost s subshell and the penultimate d subshell of transition elements. $ If so, which will be the subshell from which iron loses the third electron? $ Write the electronic configuration of Fe on the basis of this. Manganese (Mn) is the element with atomic number 25. Subshell electronic configuration. MnCl, MnO, MnO and MnO are different compounds of manganese. Complete the Table 1.17 by writing the oxidation state of manganese in each of these and also the subshell electronic configuration of each. Compound Oxidation state Subshell electronic of Mn configuration of Mn ions , 2 * 2 2 6 2 6 5 9 2 8 *  29 3 * *  29 7 * * Table & When s and p block elements take part in chemical reactions, the electrons in the outermost shell are involved. But in the case of transition elements the difference in energy between the outermost s subshell and the penultimate d subshell is very small. Hence under suitable conditions the electrons in d subshell also take part in chemical reactions. Hence transition elements show variable oxidation states. 26  Periodic Table and Electronic Configuration Coloured compounds See some compounds of the transition elements given below. Copper sulphate The catalytic property of Cobalt nitrate transition elements Potassium permanganate Catalysts are substances which influence Ferrous sulphate the speed of a chemical reaction without themselves undergoing any permanent chemical change. Generally transition....................................................................................... elements and their compounds are widely Examine these compounds available in the used as catalysts. Vanadium pentoxide science lab and find out their colours. Find more 1