Question

Which of the following trend shows the electron affinity values for the halogens?

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

Answer 1

The correct option is A

F < Cl > Br > I

In a group of non-metals, electron gain enthalpy of the $2^{nd}$ element is maximum. Among halogens, chlorine has the highest electron affinity. We would expect fluorine would have the highest electron affinity because of being a halogen and very small size, but its so small that it leads to interelectronic repulsions and the overall energy released when an electron is added is reduced. Hence, F < Cl > Br > I is the correct order of electron affinity.