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प्रश्न
In which of the following options the order of arrangement does not agree with the variation of the property indicated against it?
(i) \[\ce{Al^{3+} < Mg^{2+} < Na+ < F-}\] (increasing ionic size)
(ii) \[\ce{B < C < N < O}\] (increasing first ionisation enthalpy)
(iii) \[\ce{I < Br < Cl < F}\] (increasing electron gain enthalpy)
(iv) \[\ce{Li < Na < K < Rb}\] (increasing metallic radius)
उत्तर
(ii) \[\ce{B < C < N < O}\] (increasing first ionisation enthalpy)
(iii) \[\ce{I < Br < Cl < F}\] (increasing electron gain enthalpy)
Explanation:
The ionization enthalpy of \[\ce{N}\] is higher than that of F because it possess half filled orbital which provide it extra stability due to symmetry
As the atomic size of \[\ce{F}\] is much smaller thus its electron gain enthalpy is lower than that of the \[\ce{Cl}\]
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संबंधित प्रश्न
What is the significance of the terms - ‘isolated gaseous atom’ and ‘ground state’ while defining the ionization enthalpy and electron gain enthalpy?
Hint: Requirements for comparison purposes.
Which of the following pair of elements would have a more negative electron gain enthalpy?
F or Cl
Describe the theory associated with the radius of an atom as it loses an electron.
Among halogens, the correct order of amount of energy released in electron gain (electron gain enthalpy) is ______.
Which of the following statements are correct?
(i) Helium has the highest first ionisation enthalpy in the periodic table.
(ii) Chlorine has less negative electron gain enthalpy than fluorine.
(iii) Mercury and bromine are liquids at room temperature.
(iv) In any period, atomic radius of alkali metal is the highest.
Explain why the electron gain enthalpy of fluorine is less negative than that of chlorine.
Match the correct ionisation enthalpies and electron gain enthalpies of the following elements.
| Elements | ∆H1 | ∆H2 | ∆egH | |
| (i) Most reactive non-metal | A. | 419 | 3051 | – 48 |
| (ii) Most reactive metal | B. | 1681 | 3374 | – 328 |
| (iii) Least reactive element e | C. | 738 | 1451 | – 40 |
| (iv) Metal forming binary halide | D. | 2372 | 5251 | + 48 |
Assertion (A): Electron gain enthalpy becomes less negative as we go down a group.
Reason (R): Size of the atom increases on going down the group and the added electron would be farther from the nucleus.
Discuss the factors affecting electron gain enthalpy and the trend in its variation in the periodic table.
Assertion: The most electronegative element in the periodic table is F.
Reason: Fluorine has the highest negative electron gain enthalpy.
