Which elements show an anomalous trend in the negative value of electron gain enthalpy within their respective groups?

(A) In group $16$,the electron gain enthalpy of $S$ is more negative than that of $O$ due to the small size of the $O$ atom,which leads to inter-electronic repulsion.
In group $17$,the electron gain enthalpy of $Cl$ is more negative than that of $F$ because the small size of $F$ causes significant inter-electronic repulsion,making the addition of an electron less favorable compared to $Cl$.