NEETChemistryClassification of Elements and Periodicity in Properties
Match List-I with List-II. List-I List-II (A) F (I) -349 kJ mol ⁻¹ (B) Cl (II) -328 kJ mol ⁻¹ (C) Br (III) -325 kJ mol ⁻¹ (D) I (IV) -295 kJ mol ⁻¹ Choose the correct answer from the options given below:
Options
- A(A)-(II), (B)-(I), (C)-(III), (D)-(IV)
- B(A)-(I), (B)-(II), (C)-(III), (D)-(IV)
- C(A)-(IV), (B)-(I), (C)-(II), (D)-(III)
- D(A)-(III), (B)-(I), (C)-(II), (D)-(IV)
Correct answer
A. (A)-(II), (B)-(I), (C)-(III), (D)-(IV)
Step-by-step solution
The electron gain enthalpy generally becomes less negative down a group as atomic size increases. However, due to the extremely small size of the fluorine atom and the resulting strong interelectronic repulsions in its 2p subshell, the incoming electron experiences less attraction from the nucleus. As a result, the negative electron gain enthalpy of fluorine is lower than that of chlorine. The correct decreasing order of negative electron gain enthalpy for halogens is Cl > F > Br > I . Matching the elements with th