Question

The element with the highest electron affinity among the halogens is

• A. $\mathrm{F}$
• B. $\mathrm{Cl}$
• C. $\mathrm{Br}$
• D. $\mathrm{I}$

Answer 1

The correct option is B

$\mathrm{Cl}$

Explanation for correct option

(B)$\mathrm{Cl}$

• Electron affinity is the amount of energy released when an electron is added to a neutral atom to form an anion.
• In general the electron affinity decrease on going down the group and increase ongoing left to right in a period.
• The element with the highest electron affinity among the halogens is chlorine $\left(\mathrm{Cl}\right)$.
• Because the size of fluorine is too small as size decreases from left to right inside period, whereas in the case of chlorine due to the bigger size electron repulsion is not observed when extra electrons are added.
• So, the order of the electron affinity of halogens are $\text{Cl>F>Br>I}$

Explanation for incorrect option

(A)

• Fluorine $\left(\mathrm{F}\right)$ is the more electronegative atom, however, when extra electrons are added, repulsion occurs due to its smaller size.
• So, the electron affinity of fluorine is less compared to chlorine.

(C)

• The element with the highest electron affinity among the halogens is chlorine.
• So, option(C) is incorrect.

(D)

• The element with the highest electron affinity among the halogens is chlorine.
• So, option(D) is incorrect.

Hence, option (B) is the correct option. The element with the highest electron affinity among the halogens is $\mathrm{Cl}$.