Question

Which of the following will have the most negative electron gain enthalphy and which the least negative?

• A. F, Cl
• B. Cl,F
• C. Cl,S
• D. CL,P

Answer 1

The correct option is A F, Cl

Halogen have highest is more negative than negative value of electron gain enthalphy ,Here $Cl,F$ both are halogens but electron gain enthalphy of $Cl$is more negative than $F$ because of very small size of $F$ which causes interelectronic repulsion among its electrons.

$Cl$ has the most negative one.

$P$ has the least negative one due to greater size.