{"id":12001,"date":"2024-03-04T09:03:18","date_gmt":"2024-03-04T03:33:18","guid":{"rendered":"https:\/\/tsboardsolutions.in\/?p=12001"},"modified":"2024-03-05T14:18:36","modified_gmt":"2024-03-05T08:48:36","slug":"ts-10th-class-physical-science-solutions-chapter-8","status":"publish","type":"post","link":"https:\/\/tsboardsolutions.in\/ts-10th-class-physical-science-solutions-chapter-8\/","title":{"rendered":"TS 10th Class Physical Science Solutions Chapter 8 Chemical Bonding"},"content":{"rendered":"

Telangana SCERT TS 10th Class Physical Science Study Material Pdf<\/a> 8th Lesson Chemical Bonding Textbook Questions and Answers.<\/p>\n

TS 10th Class Physical Science 8th Lesson Questions and Answers Chemical Bonding<\/h2>\n

Improve Your Learning
\n<\/span>I. Reflections on concepts<\/span><\/p>\n

Question 1.
\nExplain the difference between the valence electrons and the covalency of an element. \\
\nAnswer:<\/p>\n\n\n\n\n\n
Valence Electrons<\/td>\nCovalency<\/td>\n<\/tr>\n
1. The electrons present in the outermost orbital of an atom are called valence electrons.<\/td>\n1. The total number of covalent bonds that an atom of an element forms is called covalency of the element<\/td>\n<\/tr>\n
2. Valence electrons depend upon the number of electrons present in that atom.<\/td>\n2. Covalency depends upon the valence electrons.<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

 <\/p>\n

Question 2.
\nA chemical compound has the following Lewis notation:
\n\"TS
\n(a) How many valence electrons does element Y have?
\n(b) What \u00a1s the valency of element Y\u2019 x . X
\n(c) What is the valency of element X?
\n(d) How many covalent bonds are there in the molecule? H
\n(e) To which groups the elements X and Y belong?
\nAnswer:
\n(a) Six electrons.
\n(b) Two. because it has combined with two elements namely X and H.
\n(c) One
\n(d) Two covalent bonds one in Y – X and another one is Y – H.
\n(e) X is Hydrogen and Y is oxygen. I suggest the molecule is H2<\/sub>O (water).<\/p>\n

Question 3.
\nHow bond energies and bond lengths of molecule help us in predicting their chemical properties? Explain with examples.
\nAnswer:
\n1. Bond length: Bond length or bond distance \u00a1s the equilibrium distance between the nuclei of two atoms which form a covalent bond.<\/p>\n

2. Bond energy: Bond energy or bond dissociation energy \u00a1s the energy needed to break a covalent bond between two atoms of a diatomic covalent compound in its gaseous state.<\/p>\n

3. If the nature of the bond between the same two atoms changes, the bond length also changes. For example, the bond lengths between two carbon atoms are C-C>C=C>C \u2261 C.<\/p>\n

4. Thus the various bond lengths between the two carbon atoms are \u00a1n ethane 1.54 \u00c5, ethylene 1.34 \u00c5. acetylene 1.20 \u00c5.<\/p>\n

5. The bond lengths between two oxygen atoms are in H2<\/sub>O<\/span>2<\/sub> (O-O) Is 1.48 A\u00b0 and in O<\/span>2<\/sub> (O = O) is 1.21 \u00c5.<\/span><\/p>\n

6. Observe the table.<\/p>\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n
Bond<\/td>\nBond length(\u00c5)<\/td>\nBond (dissociation) energy (KJ mol-1<\/sup>\u2019)<\/td>\n<\/tr>\n
H -H<\/td>\n0.74<\/td>\n436<\/td>\n<\/tr>\n
F-F<\/td>\n1.44<\/td>\n159<\/td>\n<\/tr>\n
Cl-Cl<\/td>\n1.95<\/td>\n243<\/td>\n<\/tr>\n
Br-Br<\/td>\n2.28<\/td>\n193<\/td>\n<\/tr>\n
I-I<\/td>\n2.68<\/td>\n151<\/td>\n<\/tr>\n
H-F<\/td>\n0.918<\/td>\n570<\/td>\n<\/tr>\n
H-Cl<\/td>\n1.27<\/td>\n432<\/td>\n<\/tr>\n
H-Br<\/td>\n1.42<\/td>\n366<\/td>\n<\/tr>\n
H -I<\/td>\n1.61<\/td>\n298<\/td>\n<\/tr>\n
H-O(of H2<\/sub>O)<\/td>\n0.96<\/td>\n460<\/td>\n<\/tr>\n
H-N(of NH3<\/sub>)<\/td>\n1.01<\/td>\n390<\/td>\n<\/tr>\n
H-C(of CH4<\/sub>)<\/td>\n1.10<\/td>\n410<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

7. When bond length decreases, then bond dissociation energy Increases.
\n8. When bond length increases, then bond dissociation energy decreases.
\n9. Bond length of H -H in H2<\/sub> molecule is 0.74 \u00c5 and its bond dissociation energy is 436 KJ\/mol, whereas bond length of F – F In F2<\/sub> molecule is 1.44 \u00c5 and its bond dissociation energy Is 159 K\/mol.
\n10. Melting and boiling points of substances also can be determined by these bond energies and bond lengths.<\/p>\n

Question 4.
\nDraw simple diagrams to show how electrons are arranged in the following covalent molecules:
\n(a) Calcium oxide (CaO)
\n(b) Water (H2<\/sub>O)
\n(c) Chlorine (Cl2<\/sub>)
\nAnswer:
\n(a) Calcium oxide (CaO)
\n\"TS \"\"<\/p>\n

(b) Water (H2<\/sub>O):
\n\"TS
\nOne oxygen and two hydrogen atoms form a water molecule, H2<\/sub>O<\/p>\n

(c) Chlorine (Cl2<\/sub>):
\n\"TS \"\"<\/p>\n

Question 5.
\nRepresent each of the following atoms using Lewis notation.
\n(a) Beryllium
\n(b) Calcium
\n(c) Lithium
\n(d) Bromine gas(Br2<\/sub>)
\n(e) Calcium Chloride (CaCl2<\/sub>)
\n(f) Carbon dioxide (CO2<\/sub>)
\nAnswer:
\n(a) Beryllium:
\nBeryllium atomic number = 4
\nBe – Valency electrons = 2<\/p>\n

(b) Calcium:
\nCalcium atom\u00efc number = 20
\nCa – Valency electrons = 2<\/p>\n

(C) Lithium:
\nLithium atomic number = 3
\nLi – Valency electron = 1<\/p>\n

(d) Bromine gas (Br2<\/sub>):
\n\"TS<\/p>\n

(e) Calcium Chloride (CaCl2<\/sub>):
\n\"TS<\/p>\n

(f) Carbon dioxide (CO2<\/sub>):
\n\"TS<\/p>\n

Question 6.
\nWhy do only valence electrons involve in bond formation? Why not electron of Inner shells? Explain.
\nAnswer:<\/p>\n

    \n
  1. When two atoms come sufficiently close together the valence electrons of each atom experience the attractive force of the nucleus in the other atom.<\/li>\n
  2. The nucleus and the electrons \u00a1n the inner shell remain unaffected when atoms come close together.<\/li>\n
  3. only the electrons in outermost shell of an atom get affected.<\/li>\n
  4. Thus electrons in valence shell are responsible for the formation of bond between atoms.<\/li>\n<\/ol>\n

    Question 7.
    \nList the factors that determine the type of bond that will be formed between two atoms.
    \nAnswer:
    \nThere are several factors that determine the type of bond which will be formed between two atoms. They are<\/p>\n

      \n
    • The force of attraction or repulsion between the electrons and protons.<\/li>\n
    • Number of valence electrons present in the valence shell of the atom.<\/li>\n
    • Electronegative difference between the atoms.
      \nIf the E.N difference between the two atoms is > 1.9, ionic bond is formed.
      \nIf the E.N difference between the two atoms is <1.9, covalent bond is formed.<\/li>\n
    • Atomic size<\/li>\n
    • Ionisation potential<\/li>\n
    • Electron affinity.<\/li>\n<\/ul>\n

      Question 8.
      \nRepresent the molecule H2<\/sub>O using Lewis notation.
      \nAnswer:
      \n\"TS<\/p>\n

      Question 9.
      \nWhat is octet rule? How do you appreciate the role of the ‘Octet rule’ in explaining the chemical properties of elements?
      \nAnswer:
      \nOctet rule: “The atoms of element tend to undergo chemical changes that help to leave their atoms with eight outer-shell electrons”.<\/p>\n

      \u2192 Role of ‘Octet Rule :<\/p>\n

        \n
      • ‘Octet rule’ helps to explain the chemical activities of atoms of many elements.<\/li>\n
      • It explains why some elements are more reactive towards chemical reaction and some are not.<\/li>\n
      • It can explain the high reactivity of Alkali, Alkaline earth metals.<\/li>\n
      • It can also explain the high reactivity of halogens.<\/li>\n<\/ul>\n

        Question 10.
        \nWhat is hybridization? Explain the formation of the following molecules using hybridization.
        \n(a) BeCl2<\/sub>
        \n(b) BF3<\/sub>
        \nAnswer:
        \n(i) Hybridisation is a phenomenon of intermixing of atomic orbitals of almost equal energy which are present in the outer shells of the atom and their reshuffling or redistribution into the same number of orbitals but with equal properties like energy and shape.<\/p>\n

        (a) Formation of BeCl2<\/sub> (Beryllium chloride) molecule:
        \n(ii) The atomic number of Beryllium is 4
        \n(iii) The electronic configuration of Beryllium atom in its ground state is 1s2<\/sup>2s2<\/sup>.
        \n(iv) The electronic configuration of Beryllium atom in its excited state is 1s2<\/sup> 2s1<\/sup>2p1<\/sup>.
        \n\"TS
        \n(i) In the excited Beryllium atom its ‘2s’ and ‘2px<\/sub>‘ orbitals intermix to give two equivalent ‘ sp ‘ hybrid orbitals.
        \n(ii) The electronic configuration of Be is 1S2<\/sup>2s1<\/sup>2px<\/sub>1<\/sup>. It has one half-filled ‘p’ orbital.
        \n(iii) The electronic configuration of 17 Cl is 1s2<\/sup> 2 s2<\/sup>2p6<\/sup>3s2<\/sup>3px<\/sub>2<\/sup>3py<\/sub>2<\/sup>3pz<\/sub>1<\/sup>
        \n\"TS<\/p>\n

        (iv) The half-filled 3pz<\/sub> orbitals of two chlorine atoms overlap with \u2018sp\u2019 hybrid orbitals of beryllium atom in their axes to form two \u03c3 sp-p<\/sub> bonds.
        \n(v) BeCl2<\/sub> molecule so formed has linear shape. The bond angle in BeCl2<\/sub> is 180\u00b0.
        \n\"TS<\/p>\n

        (b) Formation of Boron Trifluoride BF3<\/sub>:
        \n(i) The central atom in BF3<\/sub> is boron.
        \n(ii) The electronic configuration of boron atom in its excited state is 1s2<\/sup> 2s1<\/sup> 2p2<\/sup>
        \nB(Z=5)is
        \n\"TS
        \n(iii) In the excited boron atom 2s\u2019 orbital and two \u20182p\u2019 orbitals intermix to give three equivalent sp2<\/sup> hybrid orbitals.
        \n(iv) In the formation of BF3<\/sub> molecule, three sp2<\/sup> hybrid orbitals of boron overlap with half-filled 2pz<\/sub> orbitals of three fluorine atoms. in their axes to give three bonds.
        \n(v) BF3<\/sub> molecule so formed has trigonal planar structure.
        \n\"TS
        \n(iv) The bond angle \u00a1n BF3<\/sub> is 120\u00b0.<\/p>\n

        Application of Concepts<\/span><\/p>\n

        Question 1.
        \nExplain the formation of sodium chloride and calcium oxide on the basis of the concept of electron transfer from one atom to another atom.
        \nAnswer:
        \n1. Formation of sodium chloride (NaCl): Sodium chloride is formed from the elements sodium and chlorine. It can be explained as follows.
        \n(a) Formation of Cation: When sodium atom loses one electron to get octet electron configuration it forms a cation (Na+<\/sup>) and gets electron configuration that of Neon (Ne)
        \nNa \u2192 Na+<\/sup>+e–<\/sup>
        \nE.C: 2, 8, 1 2,8 +1<\/sub>e–<\/sup><\/p>\n

        (b) Formation of anion: Chlorine has shortage of one electron to get octet in its valence shell. So It gains the election that was lost by Na to form anion (Cl–<\/sup>) and gets electron configuration of Argon (Ar)
        \nCl + e–<\/sup> \u2192 Cl–<\/sup>
        \nE.C: 2,8,7 2,8,8<\/p>\n

        (c) Formation of the compound NaCl from ions: Transfer of electrons take place between \u2018Na\u2019 and \u2018Cl\u2019 atoms while they form Na+<\/sup> and Cl–<\/sup> ions. These oppositely charged ions get attracted towards each other due to
        \nelectrostatic forces and form the compound sodium chloride (NaCl).
        \nNa+<\/sup>(g)<\/sub> + Cl–<\/sup>(g)<\/sub> \u2192 NaCl(s)<\/sub><\/p>\n

        2. FormatIon of calcium oxide (CaO) Calcium Oxide Is formed from the elements Calcium and Oxygen. It can be explained as follows :
        \n(a) Formation of Cation: When Calcium atom loses two electrons to get octet electronic configuration it forms a cation (Ca+2<\/sup>) and gets electron configuration of Argon (Ar)
        \n\"TS<\/p>\n

        (b) Formation of anion: Oxygen has shortage of two electrons to get octet in its valence shell. So it gains the electrons that were lost by Ca to form anion (O-2<\/sup>) and gets electron configuration of Neon (Ne)
        \nO + 2e–<\/sup> \u2192 O-2<\/sup>
        \nE.C: 2, 6 \u2192 2,8<\/p>\n

        (c) Formation of the compound CaO from ions : Transfer of electrons between \u2018Ca\u2019 and \u2018O\u2019 atoms takes place while they form Ca+2<\/sup> and O-2<\/sup> ions. These oppositely charged ions get attracted towards each other due to
        \nelectrostatic forces and form the compound calcium oxide (CaO).
        \nCa+2<\/sup>(g)<\/sub> + O-2<\/sup>(g)<\/sub> \u2192CaO(s)<\/sub><\/p>\n

        Question 2.
        \nA, B and C are three elements with atomic numbers 6, 11. and 17 respectively.
        \n(i) Which of these cannot form Ionic bond? Why?
        \n(ii) Which of these cannot form covalent bond? Why?
        \n(iii) Which of these can form Ionic as well as covalent bonds?
        \nAnswer:
        \n(i) \u2018A\u2019 cannot form ionic bond. Its valence electrons are 4. It is difficult to lose or gain 4e–<\/sup> to get octet configuration. So it forms covalent bond [Z of A is 6 so it is carbon (c)].<\/p>\n

        (ii) \u2018B\u2019 cannot form covalent bond. Its valence electrons are 1 only. So it is easy to donate the electron for other atom and become an ion. So it can form ionic bond [Z of B is 11, so it is sodium (Na)].<\/p>\n

        (iii) Element C can form ionic as well as covalent bonds. The element with atomic number 17 is Cl. It is able to participate with Na in ionic bond forming NaCl and with hydrogen in HCl molecule as covalent bond.<\/p>\n

        Question 4.
        \nHow Lewis dot structure helps in understanding bond formation between atoms?
        \nAnswer:<\/p>\n

          \n
        1. The valence electrons in an atom are represented by putting dots (.)on the symbol of the element, one dot for each valence electron.<\/li>\n
        2. By knowing the valence electrons of two different atoms by Lewis dot structure, we can understand which type of bond is going to establish between them and forms corresponding molecule.<\/li>\n<\/ol>\n

          Question 5.
          \nExplain the formation of the following molecules using valence bond theory.
          \n(a) N2<\/sub> molecule,
          \n(b) O2<\/sub> molecule
          \nAnswer:
          \n(a) Formation of N2<\/sub> molecule:
          \n7<\/sub>N has electronic configuration 1s2<\/sup> 2s2<\/sup> 2px<\/sub>1<\/sup> 2py<\/sub>1<\/sup>2pz<\/sub>1<\/sup> Suppose that \u2018px<\/sub>\u2019orbital of one \u2018N\u2019 atom overlaps the \u2018px<\/sub>\u2019 orbital of the other \u2018N\u2019 atom giving \u03c3px-px<\/sub> bond along the inter-nuclear axis. The py<\/sub> and pz<\/sub> orbitals of one \u2018N\u2019 atom overlap the py<\/sub> and pz<\/sub> orbital of other \u2018N\u2019 atom laterally, respectively perpendicular to internuclear axis giving 2\u03c0 py<\/sub>-py<\/sub> and pz<\/sub> – pz<\/sub> bonds. Therefore N2<\/sub> molecule has a triple bond between two nitrogen atoms. (N \u2261 N)
          \n\"TS<\/p>\n

          b) Formation of O2<\/sub> molecule:<\/p>\n

            \n
          • 8<\/sub>O has electronic configuration 1s2<\/sup>2s2<\/sup>2px<\/sub>2<\/sup>2py<\/sub>1<\/sup>2pz<\/sub>1<\/sup><\/li>\n
          • If the \u2018py<\/sub>\u2019 orbital of one \u2018O\u2019 atom overlaps the \u2018py<\/sub>\u2019 orbital of other \u2018O\u2019 atom along the internuclear axis, a sigma py<\/sub>– py<\/sub> bond ((\u03c3py- py<\/sub>) is formed.<\/li>\n
          • pz<\/sub> orbital of one \u2018O\u2019 atom overlaps the pz<\/sub> orbital of other \u2018O\u2019 atom laterally, perpendicular to the inter-nuclear axis giving a \u03a0pz-pz<\/sub> bond.<\/li>\n
          • O2<\/sub> molecule has a double bond between two oxygen atoms. (O=O)<\/li>\n<\/ul>\n

            \"TS<\/p>\n

            Question 6.
            \nPredict the reasons for low melting points for covalent compounds when compared with ionic compounds.
            \nAnswer:<\/p>\n

              \n
            1. The melting point is low due to the weak Vander Waal\u2019s forces of attraction between the covalent molecules.<\/li>\n
            2. The force of attraction between the molecules of a covalent compound is very weak.<\/li>\n
            3. Only a small amount of heat energy is required to break these weak molecular forces, due to which covalent compounds have low melting points and low boiling points. :<\/li>\n
            4. But some of the covalent solids like diamond and graphite have, however very high melting points and boiling points.<\/li>\n<\/ol>\n

              Higher Order Thinking questions<\/span><\/p>\n

              Question 1.
              \nTwo chemical reactions are described below.
              \n(i) Nitrogen and hydrogen react to form ammonia.
              \n(ii) Carbon and hydrogen bond together to form a molecule of methane (CH4<\/sub>)
              \nFor each reaction, give
              \na) The valence of each of the atoms involved in the reaction.
              \nb) The Lewis structure of the product that \u00a1s formed.
              \nAnswer:
              \ni) Nitrogen reacts with hydrogen to form Ammonia. The reaction is
              \nN2<\/sub> + 3H2<\/sub> \u2192 2NH3<\/sub>
              \na) The valency of each atom involved in the reaction.
              \nValence of Nitrogen = 3
              \nValence of Hydrogen = 1<\/p>\n

              (b) The Lewis structure of the product that is formed
              \n\"TS<\/p>\n

              (i) Carbon reacts with hydrogen to form a molecule of methane. The reaction is
              \nC + 2H2<\/sub> \u2192 CH4<\/sub>
              \n(a) The valency of each atom involved in the reaction
              \nValence of Carbon = 4
              \nValence of Hydrogen = 1<\/p>\n

              (b) The Lewis structure of the product
              \n\"TS<\/p>\n

              Multiple choice questions<\/span><\/p>\n

              Question 1.
              \nWhich one of the following four elements is more electronegative? [ ]
              \n(a) Sodium
              \n(b) Oxygen
              \n(c) Magnesium
              \n(d) Calcium
              \nAnswer:
              \n(b) Oxygen<\/p>\n

              Question 2.
              \nAn element, 11<\/sub>X23<\/sup> forms an ionic compound with another element \u2018Y\u2019. Then the charge on the ior formed by X is [ ]
              \n(a) +1
              \n(b)+2
              \n(c) -1
              \n(d)-2
              \nAnswer:
              \n(a) +1<\/p>\n

              Question 3.
              \nAn element \u2018A\u2019 forms a chloride ACl4<\/sub>. The number electrons in the valence shell of \u2018A\u2019 is [ ]
              \n(a) 1
              \n(b) 2
              \n(c) 3
              \n(d) 4
              \nAnswer:
              \n(d) 4<\/p>\n

              Question 4.
              \nThe inert gas element which does not have octet electronic configuration in its outermost orbit is [ ]
              \n(a) Helium
              \n(b) Argon
              \n(c) Krypton
              \n(d) Radon
              \nAnswer:
              \n(a) Helium<\/p>\n

              Question 5.
              \nNumber of covalent bonds in methane molecule [ ]
              \n(a) 1
              \n(b) 2
              \n(c) 3
              \n(d) 4
              \nAnswer:
              \n(d) 4<\/p>\n

              Question 6.
              \nThe concept hybridisation of orbitals of an atoms was introduced by\u00a0 [ ]
              \n(a) Lives pooling
              \n(b) Mosley
              \n(c) Lewis
              \n(d) Kossel
              \nAnswer:
              \n(a) Lives pooling<\/p>\n

              Question 7.
              \nThe value of bond angle in Berileum chloride molecule is [ ]
              \n(a) 180\u00b0
              \n(b) 120\u00b0
              \n(c) 110\u00b0
              \n(d) 104\u00b0.31′
              \nAnswer:
              \n(a) 180\u00b0<\/p>\n

              Suggested Projects<\/span><\/p>\n

              Question 1.
              \nCollect the information about properties and uses of covalent compounds and prepare a report?
              \nAnswer:
              \nA. Properties of covalent compounds:<\/p>\n

                \n
              1. Covalent compounds are usually liquids or gases, only some of them are solids.<\/li>\n
              2. They are usually liquids or gases due to the weak force of attraction between their molecules.<\/li>\n
              3. They have usually low melting and low boiling points.<\/li>\n
              4. They are usually insoluble in water but they are soluble in organic solvents.<\/li>\n
              5. They do not conduct electricity.<\/li>\n
              6. They show molecular reactions.<\/li>\n<\/ol>\n

                Uses of covalent compounds:<\/p>\n

                  \n
                1. Covalent compounds form 99% of our body.<\/li>\n
                2. Water is a covalent compound. We know many uses of water.<\/li>\n
                3. Sugars, food substances, tea, and coffee are all covalent compounds.<\/li>\n
                4. Air we breathe in contains covalent molecules of oxygen and nitrogen.<\/li>\n
                5. Almost everything on earth other than most simple inorganic salts are covalent compounds.<\/li>\n<\/ol>\n

                  TS 10th Class Physical Science Chemical Bonding Intext Questions<\/h3>\n

                  Page 150<\/span><\/p>\n

                  Question 1.
                  \nHow do they(elements)usually exist?
                  \nAnswer:
                  \nElements usually exist as group of atoms.<\/p>\n

                  Question 2.
                  \nDo they exist as a single atom or as a group of atoms?
                  \nAnswer:
                  \nExcept inert elements, all others exist as group of atoms. Inert elements exist as single atoms.<\/p>\n

                  Question 3.
                  \nAre there elements which exist as atoms?
                  \nAnswer:
                  \nInert elements exist freely as atoms.<\/p>\n

                  Question 4.
                  \nWhy do some elements exist as molecules and some as atoms?
                  \nAnswer:
                  \nInert elements exist as atoms as they won\u2019t form any bond other atoms form bonds and exist as molecules.<\/p>\n

                  Question 5.
                  \nWhy do some elements and compounds react vigorously while others are inert?
                  \nAnswer:
                  \nElements which do not have octet conflgurtion in their valence shelf react vigorously with other elements to form stable entities and which have octet configuration in their valence shell are chemically inert in nature.<\/p>\n

                  Question 6.
                  \nWhy is the chemical formula for water H2<\/sub>0 and for sodium chloride NaCl, why not HO2<\/sub> and NaCl2<\/sub>\u2019?
                  \nAnswer:
                  \nIn water, oxygen atom bonds with two hydrogen atoms where as sodi + ion forms single bond with chloride in NaCl – ion.<\/p>\n

                  Question 7.
                  \nWhy do some atoms combine while others do not?
                  \nAnswer:
                  \nElements which do not have octet configuration in their valence shell combine with other elements and which have octet in their valence shell are chemically inert in nature.<\/p>\n

                  Question 8.
                  \nAre elements and Compounds simply made up of separate atoms Individually arranged?
                  \nAnswer:
                  \nNo. They are arranged<\/p>\n

                  Question 9.
                  \nIs there any attraction between atoms?
                  \nAnswer:
                  \nYes, there is attraction chemical bond.<\/p>\n

                  Question 10.
                  \nWhat is that holdlng them together?
                  \nAnswer:
                  \nForce of attraction called chemical bond.<\/p>\n

                  Page 152<\/p>\n

                  Question 11.
                  \nWhy there is absorption of energy in certain chemical reactions and release of energy In other reactions?
                  \nAnswer:
                  \nThe absorption of energy in chemical reactions occurs when the reactants \u2018\u2018 less chemical energy than the product where as release of energy in chemical reactions occurs when the reactants have higher chemical energy than the products.<\/p>\n

                  Question 12.
                  \nWhere the absorbed energy goes?
                  \nAnswer:
                  \nThe energy absorbed by the molecules makes electrons to reach excited s e and Increases kinetic energy of the molecule.<\/p>\n

                  Question 13.
                  \nIs there any relation to energy and bond formation between atoms?
                  \nAnswer:
                  \nThe interacting energy is the potential energy between the atoms. It is negative if the atoms are bound and positive if they can move away from each other. The interaction energy is the integral of the force over the separation distance so these two quantities are directly related. The interaction energy is turning at the equilibrium position. This value of the energy Is called the bond energy and is the energy needed to separate completely to infinity (the work that needs to be done to overcome the attractive force.)<\/p>\n

                  Question 14.
                  \nWhat could be the reason for the change in reactivity of elements?
                  \nAnswer:
                  \nNumber of valence electrons In the atoms of the element.<\/p>\n

                  Question 15.
                  \nWhat could be the reason for the less reactivity of noble gases?
                  \nAnswer:
                  \nAll the noble gases have eight electrons in the outermost shell, except Helium (He). Thus they have no valency electrons and are less reactive or not at all reactive.<\/p>\n

                  Page 155<\/span><\/p>\n

                  Question 16.
                  \nWhat have you observed from tSe above conclusions about the main groups?
                  \nAnswer:
                  \nMain group elements lose or gain electrons to get noble gas electronic configuration.<\/p>\n

                  Question 17.
                  \nWhy do atoms of elements try to combine and form molecules?
                  \nAnswer:
                  \nTo get stable electronic configuration In their valence shell.<\/p>\n

                  Page 156<\/span><\/p>\n

                  Question 18.
                  \nIs it accidental that IA to VIlA main group elements durIng chemical reactions get eight electrons In the outermost shells of their ions, similar to noble gas atoms?
                  \nAnswer:
                  \nNo. It cannot be simply accidental, Eight electrons in the outermost shell definitely gives stability to the ion or atom. Based on the above observations a statement known as The Octet Rule\u201d Is framed.<\/p>\n

                  Page 157<\/span><\/p>\n

                  Question 19.
                  \nExplain the formation of ionic compounds NaCl, MgCl2<\/sub>, Na2<\/sub>O and AlCl3<\/sub> through Lewis electron-dot symbols (formulae).
                  \nAnswer:
                  \n(1) Lewis electron-dot symbol for NacI :
                  \n\"TS
                  \nFormation of sodium chloride (NaCl) :
                  \nSodium chloride Is formed from the elements sodium and chlorine. It can be explained as follows.
                  \nNa(s)<\/sub> + 1\/2 Cl2(g)<\/sub> \u2192 Nacl(s)<\/sub><\/p>\n

                  Cation formation: When Sodium (Na) atom loses one electron to get octet electron configuration it forms a cation (Na+) and gets electron configuration that of Neon (Ne) atom.
                  \n\"TS
                  \nAnion formation: Chlorine has shortage of one electron to get octet in its valence shell. So It gains the electron from Na atom to form anion and gets electron configuration as that of argon (Ar).
                  \n\"TS
                  \nFormation of compound NaCl from its ions: Transfer of electrons between Na and cl atoms, results in the formation of Na+, and Cl- ions. These oppositely charged ions get attracted towards each other due to electrostatic forces and form the compound sodium chloride (NaCl).
                  \nNa+<\/sup>(g)<\/sub>+ Cl–<\/sup>(g)<\/sub> \u2192 Na+<\/sup>(g)<\/sub>Cl–<\/sup>(a)<\/sub> or NaCl<\/p>\n

                  2. Lewis electron-dot symbol for MgCl2<\/sub> :
                  \n\"TS
                  \nFormation of magnesium chloride (MgCl2<\/sub>) :
                  \nMagnesium chloride is formed from the elements magnesium and chlorine. The bond formation MgCl2<\/sub> in brief using chemical equation is as follows :
                  \nMg(a)<\/sub>+Cl2(g)<\/sub> \u2192 MgCl2(a)<\/sub>
                  \nCation Formation :
                  \n\"TS
                  \nAnion formation :
                  \n\"TS
                  \nThe compound MgCl2<\/sub> formation from its ions :
                  \nMg2+<\/sup> gets Ne configuration and Each Cl- gets Ar configuration.
                  \nMg2+<\/sup>(g)<\/sub> + 2Cl–<\/sup>(g)<\/sub> \u2192 MgCl2(a)<\/sub>
                  \nOne \u2018Mg\u2019 atom transfers two electrons one each to two \u2018Cl\u2019 atoms and so formed Mg2+<\/sup> and 2Cl- attract to form MgCl2<\/sub>.<\/p>\n

                  3. Lewis electron-dot symbol for (Na2<\/sub>O) :
                  \n\"TS
                  \nFormation of di-sodium monoxide (Na2<\/sub>O) :
                  \nDi-sodium monoxide formation can be explained as follows :
                  \nCation formation (Na+ formation) :
                  \n\"TS
                  \nAnion formation (O2-, the oxide formation) Electronic configuration
                  \n\"TS
                  \nThe compound Na20 formation from Its ions is as shown.
                  \n2Na+<\/sup>(g)<\/sub> + O2-<\/sup>(g)<\/sub> \u2192 Na2<\/sub>O(g)<\/sub>
                  \nTwo \u2018Na; atoms transfer one electrons each to one oxygen atom to form 1Na+ and 02-.
                  \nEach Na+ gets \u2018Ne\u2019 configuration and 02- gets \u2018Ne\u2019 configuration.
                  \nThese ions (2Na+ and 02-) attract to form Na2O.<\/p>\n

                  4. Lewis electron-dot symbol for (AlCl3<\/sub>) :
                  \n\"TS
                  \nFormation of aluminium chloride (AlCl3<\/sub>) :
                  \nAluminium chloride formation can be explained as follows :
                  \nFormation of aluminium ion (Al3+)0 the cation :
                  \n\"TS
                  \nFormation of chloride ion (Cl-) the anIon :
                  \n\"TS
                  \nEach aluminium atom loses three electrons and three chlorine atoms gain them, one electron each. The compound AlCl3<\/sub> is formed from its component Ions by the electrostatic forces of attraction.
                  \nAl+ 3<\/sup>(g)<\/sub>+3Cl–<\/sup>(g)<\/sub><\/p>\n

                  Page 160<\/span><\/p>\n

                  Question 20.
                  \nHow do cations and anions of an ionic compound exIst in its solid state?
                  \nAnswer:
                  \nCations and anions are surrounded themselves In three-dimensional lattices to give properly shaped crystals.<\/p>\n

                  Question 21.
                  \nDo you think that pairs of Na+<\/sup> Cl–<\/sup> as units would be present in the solid crystal?
                  \nAnswer:
                  \nNo, electrostatic forces are non-directional. Therefore, it is not possible for one Na+<\/sup> to be attracted by one Cl–<\/sup> and vice-versa. Depending upon the size and charge of a particular ion, number of oppositely charged Ions get attracted by it, but, in a definite number. In sodium chloride crystal each Na is surrounded by 6 Cl–<\/sup> and each Cl–<\/sup> by six Na ions. Ionic compounds in the crystalline state consist of orderly arranged cations and anions held together by electrostatic forces of attractions in three dimensions<\/p>\n

                  Page 161<\/span><\/p>\n

                  Question 22.
                  \nCan you explain the reasons for all these?
                  \nAnswer:
                  \nAn ionic bond is formed between atoms of elements with electronegativity difference equal to or greater than 1.9.<\/p>\n

                  Page 162<\/span><\/p>\n

                  Question 23.
                  \nCan you say what type of bond exists between atoms of nitrogen molecules?
                  \nAnswer:
                  \nTriple Bond<\/p>\n

                  Page 164<\/span><\/p>\n

                  Question 24.
                  \nWhat do you understand from bond lengths and bond energies?
                  \nAnswer:
                  \nBonds formed between two atoms in different molecules have different bond lengths and bond energies<\/p>\n

                  Page 165<\/span><\/p>\n

                  Question 25.
                  \nAre the values not different for the bonds between different types of atoms?
                  \nAnswer:
                  \nDifferent for different molecules.<\/p>\n

                  Page 167<\/span><\/p>\n

                  Question 26.
                  \nWhat is the bond angle in a molecule?
                  \nAnswer:
                  \nIt is the angle subtended by two imaginary lines that pass from the nuclei of two atoms which form the covalent bonds with the central atom through the nucleus of the central atom at the central atom.<\/p>\n

                  Page 169<\/span><\/p>\n

                  Question 27.
                  \nHow is HCl molecule formed?
                  \nAnswer:
                  \nThe \u2018is\u2019 orbital of \u2018H\u2019 atom containing unpaired electron overlaps with \u20183p\u2019 orbital of chlorine atom containing unpaired electron of opposite spin.<\/p>\n

                  TS 10th Class Physical Science Chemical Bonding Activities<\/h3>\n

                  Activity 1<\/span><\/p>\n

                  Question 1.
                  \nWrite the Lewis structure of the given elements \u00a1n the table. Also, consult the periodic table and fill in the group number of the element.
                  \nAnswer:
                  \n\"TS<\/p>\n

                  Question 2.
                  \nLook at the periodic table. Do you see any relation between the number of valence electrons and group numbers\u2019?
                  \nAnswer:
                  \nFor groups 2-6 the number of valence electrons is its group number. Group 1 has one outer electron, group 2 has two, where groups 13-17 number of valence electrons is (Group number-10). 3, 2, 1 respectively. (ie, 8-5=3;8-6=2;8-7= 1)<\/p>\n

                  Question 3.
                  \nWhat did you notice in Lewis dot structure of noble gases and electronic configurations of the atoms of these elements shown in table – 1.
                  \nAnswer:
                  \nIt was found that the elements get octet or ns2 np6 configuration except helium, duplet.<\/p>\n","protected":false},"excerpt":{"rendered":"

                  Telangana SCERT TS 10th Class Physical Science Study Material Pdf 8th Lesson Chemical Bonding Textbook Questions and Answers. TS 10th Class Physical Science 8th Lesson Questions and Answers Chemical Bonding Improve Your Learning I. Reflections on concepts Question 1. Explain the difference between the valence electrons and the covalency of an element. \\ Answer: Valence … Read more<\/a><\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[16],"tags":[],"jetpack_featured_media_url":"","_links":{"self":[{"href":"https:\/\/tsboardsolutions.in\/wp-json\/wp\/v2\/posts\/12001"}],"collection":[{"href":"https:\/\/tsboardsolutions.in\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/tsboardsolutions.in\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/tsboardsolutions.in\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/tsboardsolutions.in\/wp-json\/wp\/v2\/comments?post=12001"}],"version-history":[{"count":5,"href":"https:\/\/tsboardsolutions.in\/wp-json\/wp\/v2\/posts\/12001\/revisions"}],"predecessor-version":[{"id":12858,"href":"https:\/\/tsboardsolutions.in\/wp-json\/wp\/v2\/posts\/12001\/revisions\/12858"}],"wp:attachment":[{"href":"https:\/\/tsboardsolutions.in\/wp-json\/wp\/v2\/media?parent=12001"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/tsboardsolutions.in\/wp-json\/wp\/v2\/categories?post=12001"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/tsboardsolutions.in\/wp-json\/wp\/v2\/tags?post=12001"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}