Which one of the following arrangements represents the correct order of electron gain enthalpy of the given atomic species?

Options

A. `Cl lt F lt S lt O`
B. `O lt S lt F lt Cl`
C. `S lt O lt Cl lt F`
D. `F lt Cl lt O lt S`

Answer

B

Explanation

Halogens have very high electron affinity. It may be rated that the electron affinity of fluorine is unexpectedly low `(lt Cl)`. This may perhaps be due to small size of F atom. The value of electron gain enthalpies for `Cl, F, S` and O are respectively 349, 333, 200 and 142 kJ/mol, hence correct order is `Cl gt F gt S gt O`.