Author: Dr. Vikas Jasrotia

Chemical Bonding and Molecular Structure – Short Notes Chemical Bonding and Molecular Structure Kossel-Lewis Concept: Atoms take part in chemical combinations to complete octets in their valence shell. This is known as the octet rule. Limitation of Octet Rule: The octet rule, though useful but have some exceptions e.g. BF3, NO2, PCl5, SF6, etc. Lewis Symbol or Electron Dot Structure: Representing valence electrons by dots placed around the letter symbol of the element. Types of Chemical Bonds: (i) Covalent Bond: (a) Formed by sharing of electrons. (b) It may be polar or nonpolar. (c) It is directional in nature. (ii)…

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Que: What is the difference between a Reversible and an Irreversible process? Reversible Process   Irreversible Process 1 It is a process that follows a reversible path. 1 It is a process that follows an irreversible path. 2 It is a spontaneous process and takes a finite time. 2 It is an ideal process and takes infinite time. 3 In this process, the opposing and driving forces differ only by an infinitesimally small magnitude. 3 There is a considerable difference between driving and opposing force 4 Work obtained is maximum. 4 Work obtained is not maximum. 5 It is…

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Que: Define the octet rule. Write its significance and limitations. Ans: The octet rule or the electronic theory of chemical bonding was developed by Kossel and Lewis. According to this rule, atoms can combine either by transfer of valence electrons from one atom to another or by sharing their valence electrons in order to attain the nearest noble gas configuration by having an octet in their valence shell. The octet rule successfully explained the formation of chemical bonds depending on the nature of the element. Limitations of the octet theory: The following are the limitations of the octet rule: (a)…

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Que: Arrange the following in each as instructed (i)    O, F, S, Cl, N in order of increasing strength of hydrogen bonding (X — H – X). (ii)  N2, O2, F2, Cl2 in increasing order of bond dissociation energy. Ans: (i)  Strength of hydrogen bonding depends on the electronegativity of the atom linked with hydrogen. Thus the order is S < Cl < N < O < F (ii) The increasing order is F2 < Cl2 < O2 < N2. Both fluorine and chlorine atoms in F2 and Cl2 possess three non-bonded electron pairs each. Due to the small…

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Metals and Non-Metals Class 10 – Important Points The post Metals and Non-Metals Class 10 – Important Points is about the summary of the whole chapter Metals and Non-Metals Class 10. Metals are lustrous, malleable, ductile and have high density. Metals are generally good conductors of heat and electricity. Metals form positive ions by losing electrons. All metals combine with oxygen to form metal oxides. Metal oxides are basic in nature. Metals react with chlorine to form electrovalent chloride of metals. Metals like Li, Na and Ca form hydrides with hydrogen. There are metal-bearing substances below the earth’s surface which…

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Chemical Bonding MCQ For NEET Solved – PDF Chemical Bonding MCQ For NEET Que 1. Which of the following molecules is adequately represented by a single Lewis structure? (a) O3 (b) NOCl (c) SO2 (d) N2O Ans 1. (b) Reason: NOCl can be represented with only one Lewis diagram O::N:Cl. We cannot write other Lewis diagrams for NOCl but for other molecules, more than one Lewis diagram can be written. Que 2. Among LiCl, BeCl2, BCl3, and CCl4, the covalent bond character follows the order (a) BeCl2 > BCl3 > CCl4 < LiCl (b) BeCl2 < BCl3 < CCl4 <…

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Class 11 Chemistry Case Study Questions – Chapter 1   Class 11 Chemistry Case Study Questions In these questions, a statement of Assertion followed by a statement of Reason is given. Choose the correct answer out of the following choices: (a) Assertion and Reason both are correct statements and Reason is the correct explanation for Assertion. (b) Assertion and Reason both are correct statements but Reason is not a correct explanation for Assertion. (c) Assertion is a correct statement but Reason is an incorrect statement. (d) Assertion is an incorrect statement but Reason is a correct statement. Read the passage…

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Que. Write down the conclusion made from the α-scattering experiment and the defects of the Rutherford model of the atom. Ans. Conclusions of α-scattering experiment (a) Most of the space in the atom is empty as most of the α-particles passed undeflected. (b) A few positively charged α-particles were deflected. This shows that they are deflected by the small positively charged body in the atom. (c) The positively charged body called the nucleus is very small of radius 10–15 m as compared to the radius of the atom which is about 10–10 m. Defects: (i) Position of electrons: The exact…

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Periodic Table NEET Questions PDF – Solved MCQs Periodic Table NEET Questions PDF Que 1. Identify the correct order of the size of the following: (a) Ca2+ < K+ < Ar < Cl– < S2– (b) Ar < Ca2+ < K+ < Cl– < S2– (c) Ca2+ < Ar < K+ < Cl– < S2– (d) Ca2+ < K+ < Ar < S2– < Cl– Ans 1. (a) Ca2+ < K+ < Ar < Cl– < S2– For isoelectronic species, the size of anion increases as the negative charge increases whereas the size of cation decreases with an increase in…

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Structure of Atom NEET Questions (Solved MCQs) Structure of Atom NEET Questions Que 1. A packet of energy is called (a) Electron (b) Photon (c) Position (d) Proton Ans 1. (b) Photon Que 2. Among the following the false statement is (a) Compared to the mass of the lightest nucleus the mass of the electron is only about 1/1836. (b) The ratio of e/m, i.e., specific charge for a cathode ray is constant. (c) Among He2+, H+, He+, and H the species having the highest e/m ratio is He2+. (d) The e/m for positive rays in comparison to cathode rays is…

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