Grade 12Physical Chemistry

Which of the following pairs of elements would have a more negative electron gain enthalpy? (i) O or F (ii) F or Cl

sudhanshu

12 Years agoGrade 12

3 Answers

Gaurav

11 Years ago

i. Electron gain enthalpy depends on the size of element. Smaller the size, more negative would be the electron gain enthalpy. F is of smaller size than O thus electron gain enthalpy of F is more negative than O.
ii. Cl is larger in size as compare to Cl, still electron gain enthalpy of Cl is more negative than that of F, This is due to the fact that F is very small in size due to which interelectronic repulsion takes place and the incoming electron does not feel so much attraction.

Shruti

7 Years ago

i) negative value of electron gain enthalpy increases as we move from left to right acroos a period as the size of element decreases and it easier for the elements to attract electron towards them and thus releasing more energy while attaining a stable state therefore F has more negative electron gain enthalpy as compared to that of O.

ii)Generally the negative value of electron gain enthalpy decreases down a group but in case of O and F the electron is to be added in n=2 quantum level and electron experiences significant repulsion whereas while adding the electron to their succeeding elements it enters in n=3 quantum level and experiences less repulsion thus releasing more energy hence Cl has more negative electron gain enthalpy than F.

Kushagra Madhukar

5 Years ago

Dear student,

Please find the solution to your question.

1)Electron gain enthalpy depends on the size of element. Smaller the size, more negative would be the electron gain enthalpy. F is of smaller size than O thus electron gain enthalpy of F is more negative than O.

2)Cl is larger in size as compare to Cl, still electron gain enthalpy of Cl is more negative than that of F, This is due to the fact that F is very small in size due to which interelectronic repulsion takes place and the incoming electron does not feel so much attraction.

Thanks and regards,

Kushagra