Among halogens, the correct order of amount of energy released in electron gain (electron gain enthalpy) is:
1.
F > Cl > Br > I
2.
F < Cl < Br < I
3.
F < Cl > Br > I
4.
F < Cl < Br > I
HINT: Generally down the group electron gain enthalpy decreases.
Explanation:
As we move from Cl to I, the electron gain enthalpy (i.e., energy released in electron gain) become less and less negative due to a corresponding increase in the atomic size.
However, the electron gain enthalpy of F is less negative than that of Cl due to its small size.
Thus, the negative electron gain enthalpy follows the order :
