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प्रश्न
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.
विकल्प
Assertion and reason both are correct statements but reason is not correct explanation for assertion.
Assertion and reason both are correct statements and reason is correct explanation for assertion.
Assertion and reason both are wrong statements.
Assertion is wrong statement but reason is correct statement.
उत्तर
Assertion is wrong statement but reason is correct statement.
Explanation:
The electron gain enthalpy decreases down the group due to the increase in the atomic size which leads to decrease in the effective nuclear charge.
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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.
Describe the theory associated with the radius of an atom as it gains an electron.
Describe the theory associated with the radius of an atom as it loses an electron.
Which of the following pair of elements would have a more negative electron gain enthalpy?
O or F
The formation of the oxide ion, \[\ce{O2- (g)}\], from oxygen atom requires first an exothermic and then an endothermic step as shown below:
\[\ce{O (g) + e- -> O- (g) ; ∆H^Θ = - 14 kJ mol^{-1}}\]
\[\ce{O- (g) + e- -> O^{2-} (g) ; ∆H^Θ = + 780 kJ mol^{-1}}\]
Thus process of formation of \[\ce{O^{2-}}\] in gas phase is unfavourable even though \[\ce{O^{2-}}\] is isoelectronic with neon. It is due to the fact that,
Explain why the electron gain enthalpy of fluorine is less negative than that of chlorine.
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): Boron has a smaller first ionisation enthalpy than beryllium.
Reason (R): The penetration of a 2s electron to the nucleus is more than the 2p electron hence 2p electron is more shielded by the inner core of electrons than the 2s electrons.
Discuss the factors affecting electron gain enthalpy and the trend in its variation in the periodic table.
The correct order of electron gain enthalpy (−ve value) is ______.
