Question

The absolute value of the electron gain enthalpy of halogen satisfies-

• A. I > Br >Cl> F
• B. F >Cl> Br > I
• C. Cl> F > Br > I
• D. Cl> Br > F > I

Answer 1

The correct option is C

Cl> F > Br > I

Explanation for the correct answer:

Option (C) Cl > F > Br > I

• The amount of energy released when an electron is added to an isolated gaseous atom is called electron gain enthalpy or electron affinity.
• Chlorine being larger than Fluorine, has more electron gain enthalpy than fluorine.
• This is because the electron density in Chlorine is less than that of Fluorine.
• Due to the small size of Fluorine there is interelectronic repulsion, hence due to this the electron gain enthalpy of Fluorine is less than Chlorine.
• We also know that, on moving down the group electron gain enthalpy decrease due to an increase in atomic size.
• Thus, Chlorine has more electron gain enthalpy than Bromine followed by Iodine.
• therefore, the correct order is Cl> F > Br > I
• Hence it is the correct option.

Therefore, option (C) Cl > F > Br > I is the correct answer.