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प्रश्न
Describe the theory associated with the radius of an atom as it loses an electron.
उत्तर १
When an atom loses an electron, the number of electrons decreases by one while the nuclear charge remains the same. Therefore, the interelectronic repulsions in the atom decrease. As a result, the effective nuclear charge increases. Hence, the radius of the atom decreases.
उत्तर २
Loss of an electron from an atom results in the formation of a cation. A cation is smaller than its parent atom because it has fomer electrons while its nuclear charge remains the same. For example, The atomic radius of sodium (Na) is 186 pm and atomic radius of sodium ion (Na+) = 95 pm
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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 gains an electron.
Which of the following pair of elements would have a more negative electron gain enthalpy?
O or F
Among halogens, the correct order of amount of energy released in electron gain (electron gain enthalpy) is ______.
Which of the following elements will gain one electron more readily in comparison to other elements of their group?
(i) \[\ce{S (g)}\]
(ii) \[\ce{Na (g)}\]
(iii) \[\ce{O (g)}\]
(iv) \[\ce{Cl (g)}\]
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 |
Electronic configuration of some elements is given in Column I and their electron gain enthalpies are given in Column II. Match the electronic configuration with electron gain enthalpy.
| Column (I) | Column (II) |
| Electronic configuration | Electron gain enthalpy/kJ mol–1 |
| (i) 1s2 2s2 sp6 | (A) – 53 |
| (ii) 1s2 2s2 2p6 3s1 | (B) – 328 |
| (iii) 1s2 2s2 2p5 | (C) – 141 |
| (iv) 1s2 2s2 2p4 | (D) + 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.
The correct order of electron gain enthalpy (−ve value) is ______.
