Question

# Which of the following has the highest electron affinity?(A) K (B) ${{O}^{-}}$ (C) ${{F}^{-}}$ (D) O

Fluorine and Oxygen have high electronegativity and hence they have high electron affinity. In between, Oxygen and fluorine , fluorine have the high electron affinity but, here ${{F}^{-}}$, since fluorine is smaller in size so ${{F}^{-}}$ will experience greater repulsion and therefore , it will require more energy to give electron to ${{F}^{-}}$. Also ${{F}^{-}}$ will acquire noble gas configuration after addition of one more electron, so it will release more energy, therefore it will have the highest electron affinity.