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NATIONAL INSTITUTE OF OPEN SCHOOLING

Senior Secondary Course - Chemistry (313)

Test 02 - Based on Lesson 2: Atomic Structure and Lesson 4: Chemical Bonding

NIOS Pattern Question Paper

Time: 3 Hours Maximum Marks: 80
Name: Enrollment No.:
Instructions:
Section A - Multiple Choice Questions (16 × 1 = 16 Marks)
  1. Which fundamental particle was discovered by J. J. Thomson in 1897? [1]
    A. Proton
    B. Electron
    C. Neutron
    D. Positron
  2. The atomic number of an element is equal to the number of: [1]
    A. Neutrons
    B. Protons
    C. Nucleons
    D. Orbitals
  3. Which isotope of uranium is used in nuclear reactors? [1]
    A. 238U
    B. 235U
    C. 234U
    D. 239U
  4. Which hydrogen spectral series lies in the visible region? [1]
    A. Lyman series
    B. Balmer series
    C. Paschen series
    D. Pfund series
  5. According to E = hν, the energy of a photon is directly proportional to its: [1]
    A. Wavelength
    B. Frequency
    C. Speed
    D. Mass
  6. The outermost shell of an atom is called the: [1]
    A. K-shell
    B. Core shell
    C. Valence shell
    D. Nuclear shell
  7. The bond formed by transfer of electrons from one atom to another is called: [1]
    A. Covalent bond
    B. Ionic bond
    C. Hydrogen bond
    D. Metallic bond
  8. VSEPR theory explains molecular shapes on the basis that electron pairs: [1]
    A. attract one another strongly
    B. remain fixed at the nucleus
    C. arrange themselves to minimize repulsion
    D. always form double bonds
  9. The hybridisation of carbon in methane, CH4, is: [1]
    A. sp
    B. sp2
    C. sp3
    D. dsp2
  10. The geometry of BF3 is: [1]
    A. Linear
    B. Bent
    C. Trigonal planar
    D. Tetrahedral
  11. Which species contains a coordinate covalent bond? [1]
    A. NaCl
    B. H2
    C. NH4+
    D. Cl2
  12. The bond order in N2 is: [1]
    A. 1
    B. 2
    C. 3
    D. 4
  13. Wave number is equal to: [1]
    A. νλ
    B. 1/λ
    C. h/λ
    D. cλ
  14. A proton is approximately how many times heavier than an electron? [1]
    A. 840
    B. 1840
    C. 2840
    D. 3840
  15. The correct order of repulsion among electron pairs is: [1]
    A. BP-BP > LP-BP > LP-LP
    B. LP-BP > BP-BP > LP-LP
    C. LP-LP > LP-BP > BP-BP
    D. BP-BP > LP-LP > LP-BP
  16. The bent shape of water is due to the presence of: [1]
    A. no lone pair on oxygen
    B. two lone pairs on oxygen
    C. one unpaired electron on oxygen
    D. a coordinate bond in water
Section B - Short Answer Questions (12 × 2 = 24 Marks)
  1. Define atomic number and mass number. Write the relation connecting them with the number of neutrons. [2]
  2. Differentiate between isotopes and isobars with one example of each. [2]
  3. State any two observations of Rutherford’s alpha-particle scattering experiment. [2]
  4. Write any two postulates of Bohr’s atomic model. [2]
  5. Define wavelength and frequency. Write the relation between them. [2]
  6. Calculate the energy of a photon of frequency 6.0 × 1014 s-1. Take h = 6.626 × 10-34 J s. [2]
  7. Define ionic bond. Show the formation of NaCl by writing the ionic equations. [2]
  8. State any two characteristics of ionic compounds. [2]
  9. What is a covalent bond? Distinguish between a bond pair and a lone pair. [2]
  10. Define dipole moment and write its expression. [2]
  11. State VSEPR theory. What is the shape of NH3 according to this theory? [2]
  12. What is hybridisation? Name the hybridisation and shape of BeCl2 and CH4. [2]
Section C - Very Short Answer Questions (9 × 2 = 18 Marks)
  1. What are valence electrons? How many valence electrons are present in oxygen? [2]
  2. Name the three isotopes of hydrogen. [2]
  3. Write the relation E = hν and state the meaning of each symbol. [2]
  4. Define wave number and write its relation with wavelength. [2]
  5. Write the equations for the formation of Na+ and Cl-. [2]
  6. Give one example each of an ionic compound and a covalent compound. [2]
  7. What is a lone pair? Give one example of a molecule containing a lone pair. [2]
  8. State the geometry of BF3 and CH4. [2]
  9. What is a coordinate covalent bond? Give one example. [2]
Section D - 3 Mark Questions (4 × 3 = 12 Marks)
  1. Describe Rutherford’s gold foil experiment and give its main conclusions. [3]
  2. Why could Rutherford’s model not explain atomic stability? State how Bohr’s model improved the situation. [3]
  3. Differentiate between ionic compounds and covalent compounds on any three points. [3]
  4. Using VSEPR theory, explain why H2O has a bent shape. [3]
Section E - 5 Mark Questions (2 × 5 = 10 Marks)
  1. Explain sp, sp2 and sp3 hybridisation with one example and geometry of each. [5]
  2. Explain the formation of NaCl on the basis of electron transfer. Why does high lattice energy help in the stability of ionic compounds? [5]