Important three mark questions Periodic Classification Of Elements - II

11th Standard

    Reg.No. :


Answer any fifty of the following questions
Time : 02:30:00 Hrs
Total Marks : 150

    Part - A

    54 x 3 = 162
  1. Explain how electronegativity values are used to predict the nature of the bond between two atoms between A and B

  2. Which of the following species will have the largest and smallest size?

  3. Given the formula of the species that will be isoelectronic with the following atoms or ions
    (i) Ar (ii) F- (iii) K+ (iv) S-2

  4. Which of the following pairs of elements would you expect to have higher ionisation energy?(i) CI or F, (ii) S or CI, (iii) Na or Ne, (iv)Ar or Kr.

  5. (i) Why has chlorine higher electron affinity than fluorine?
    (ii) Why has nitrogen has higher 1st ionisation potential than oxygen atom?
    (iii) Why has magnesium higher I.E. than aluminium atom?

  6. The first (lE1) and the second (IE2) ionisation enthalpies of three elements, I, II and III are given below:

      I II III
    IE1 403 549 1142
    IE2 2640 1060 2080

    Identify the element which is likely to be
    (i) a non-metal
    (ii) an alkali metal.
    (iii) an alkaline earth metal

  7. Assign the position of the element having outer electronic configuration
    (i) ns2 np4 for n = 3.
    (U) (n - 1) d2ns2 for n = 4.
    (iii) (n - 2)[7 (n - 1)dI ns2 for n = 6 in the periodic table.

  8. What is the significance of the terms "isolated gaseous atom" and "ground state" while defining ionisation energy and electron affinity?

  9. Among the second period elements, the actual ionisation energies are in.the order Li < B < Be < C < 0 < N < F < Ne Explain - Why? 
    (i) Be has higher IE than Boron.
    (ii) Oxygen has lower IE than nitrogen and fluorine.

  10. What are the factors due to which the ionisation energy of the main group elements tends to decrease down the group?

  11. Would you expect the second electron gain enthalpy of oxygen as positive, more negative, or less negative than the first. Justify your answer.

  12. The energy of an electron in the ground state of the hydrogen atom is -2.18 x10-18J. Calculate the ionisation energy of atomic hydrogen in J mol-1

  13. Calculate the screening constants of alkali metals for valency electrons.

  14. Calculate the screening constants of members of second period for valency electrons.

  15. A student reported the ionic radii of isoelectronic species X3+,Y2+ and Z- as 136 pm,64 pm and 49 pm respectively.Is that oreder correct?Comment

  16. Why there is a need for classification of elements?

  17. Prove that the halogens, chlorine, bromine and iodine follow the law of triads.

  18. What are the salient features of Newland's law of octaves?

  19. How the properties of Eka-silicon was related to germanium?

  20. Compare the properties of Eka-aluminium and gallium.

  21. How Moseley determined the atomic number of an element using X-rays?

  22. What are the reasons behind the Moseley's attempt in finding atomic number?

  23. Draw a simplified form of periods and elements present in modern period table.

  24. Write the electronic configuration of alkali metals 3Li,11Na,19K,37Rb,55Cs and 87Fr

  25. Explain about the classification of elements based on electronic configuration.

  26. Write about the electronic configuration of 1st and 2nd period.

  27. How many elements are there in 4th period? Prove it.

  28. How many elements are there in 6th period? Prove it.

  29. What are the two exceptions of block division in the periodic table?

  30. Explain about the salient features of metals.

  31. What are the various factors due to which the ionization enthalpy of the main group elements tends to decrease down the group?

  32. Which of the following pairs of elements would have more negative electron gain enthalpy? (I) O or F(ii) For Cl.

  33. Would you expect the second electron gain enthalpy of O as positive, more negative or less negative than the first? Justify your answer.

  34. What are major differences between metals and non-metals?

  35. The increasing order of reactivity among group 1 elements is Li < Na < K < Rb < Cs whereas that of group 17 is F > Cl > Br > I. Explain.

  36. Arrange the following as stated: (I) N2, O2, F2, Cl2 (Increasing order of bond dissociation energy) (ii) F, Cl, Br, I (Increasing order of electron gain enthalpy) (iii) F2, N2, Cl2, O2 (Increasing order of bond length).

  37. The first ionization enthalpy of magnesium is higher than that of sodium. On the other hand, the second ionization enthalpy of sodium is very much higher than that of magnesium. Explain.

  38. Give reasons:
    (I) IE1 of sodium is lower than that of magnesium whereas IE2 of sodium is higher than that of magnesium.
    (ii) Noble gases have positive value of electron gain enthalpy.

  39. Mention some characteristics of ionization energy.

  40. Why ionization energy and electron affinity are calculated in gaseous state?

  41. How is screening effect of inner electrons affect ionization energy?

  42. Ionization energy of Mg is greater than that of AI. Why?

  43. What are all the factors that influences electron gain enthalpy?

  44. Explain about the periodic variation of electron gain enthalpy in a period and in a group.

  45. Explain about the electronegativity and non-metallic character across the period and down the group.

  46. Prove that valency is a periodic property.

  47. Write a note about periodic trends and chemical reactivity.

  48. How would you explain the fact that the first ionization enthalpy of sodium is lower than that of magnesium but its second ionization enthalpy is higher than that of magnesium?

  49. Explain about the characteristics of non-metals.

  50. Periodic change in electronic configuration is responsible for the physical and chemical properties of element. Justify this statement.

  51. What is covalent radius? How would you.determine the covalent radius of chlorine atom?

  52. Write a note about metallic radius.

  53. Arrange Na+, Mg2+ and Al3+in the increasing order of ionic radii.Give reason.

  54. Arrange the ions F-, O2- and N3- in the increasing order of their ionic radii.Give reason.


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