Atomic Structure Important Questions

9th Standard

    Reg.No. :
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Science

Time : 01:00:00 Hrs
Total Marks : 50
    5 x 1 = 5
  1. Among the following the odd pair is

    (a)

    8O18, 17cl37

    (b)

    18Ar40,7N14

    (c)

    14Si30, 15pd31

    (d)

    24cr54, 19K39

  2. The term nucleons refer to

    (a)

    Protons and electrons

    (b)

    only Neutrons

    (c)

    electrons and neutrons

    (d)

    Protons and neutrons

  3. The correct electronic configuration of potassium is

    (a)

    2,8,9

    (b)

    2,8,1

    (c)

    2,8,8,1

    (d)

    2,8,8,3

  4. Law of multiple proportions was proposed by _________

    (a)

    J. Ritcher

    (b)

    Rutherford

    (c)

    John Dalton

    (d)

    J.J Thomson

  5. An alpha particle is identical with a ___________Nucleus.

    (a)

    Argon

    (b)

    Chlorine

    (c)

    Neon

    (d)

    Helium

  6. 6 x 1 = 6
  7. Calcium and Argon are examples of a pair of __________

    ()

    isobars     

  8. _________isotope is used in the treatment of goiter

    ()

       iodine 131

  9. The valency of Argon is ________

    ()

       zero

  10. The law of reciprocal proportions was proposed by

    ()

    Jeremias Ritcher

  11. Matter consists of very small and indivisible particles called________

    ()

    Atoms

  12. __________has no neutron.

    ()

    Hydrogen

  13. 5 x 1 = 5
  14. In an atom, electrons revolve around the nucleus in fixed orbits

    (a) True
    (b) False
  15. Smaller the size of the orbit, lower is the energy of the orbit

    (a) True
    (b) False
  16. The maximum number of electron in L Shell is 10

    (a) True
    (b) False
  17. Atoms of an element combine in small whole numbers to formmolecules.

    (a) True
    (b) False
  18. Orbit is the path by which electrons revolve around the nucleus. 

    (a) True
    (b) False
  19. 5 x 1 = 5
  20. Dalton

  21. (1)

    First atomic theory

  22. Rutherford

  23. (2)

    Gay Lussac

  24. Mass of proton

  25. (3)

    Planetary model

  26. Law of multiple proportion·

  27. (4)

    1.67 x 10-24g

  28. Law of combining volumes

  29. (5)

    John Dalton

    5 x 2 = 10
  30. Name an element which has the same number of electrons in its first and second shell

  31. Compare the charge and mass of protons and electrons.

  32. Ca2+ has completely filled outer shell. Justify your answer

  33. Arrange the following in the increasing order of atomic number
    Calcium, Silicon, Boron, Magnesium, Oxygen, Helium, Neon, Sulphur, Fluorine and Sodium

  34. Copy the following and write the names of the laws and their simple definitions in the space provided.

  35. 3 x 3 = 9
  36. Methane burns in oxygen to form carbon dioxide and water vapour as given by the equation
    CH4(g) + 2O2(g) ➝ CO2(g)+ 2H2O(g)
    Calculate: (i) the volume of oxygen needed to burn completely 50 cm3 of methane and (ii) the volume of carbon dioxide formed in this case.

  37. List the uses of isotopes?

  38. Draw the structure of oxygen and sulphur atoms

  39. 2 x 5 = 10
  40. Hydrogen sulphide (H2S) contains 94.11% sulphur, water (H2O) contains 11.11% hydrogen and sulphur dioxide (SO2) contains 50% of oxygen. Show that the results are in agreement with the law of reciprocal proportions

  41. Explain the postulates of Bohr’s atomic model

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