Question

Total number of correct orders of electron affinity values among the following are:
(a) $F>Cl$
(b) $O>O^{-}$
(c) ${Ne}^{+}$ < F
(d)$F>F^{-}$

Answer 1

(a) Halogens have seven electrons in their valance shells. Therefore, they tend to accept one electron for a stable electronic configuration. It is easier for the halogens to gain electrons to fulfil a stable octet. But the second electron affinity is positive and because of the no tendency to accept an additional electron. The order $F>Cl$ is incorrect.

(b) For $O$, two electrons are required to complete the octet configuration. The second electron affinity of oxygen is particularly high because the electron is being forced into a small, very electron-dense space. We are forcing an electron into an already negative ion. It's not going to go in willingly. EA of $O>O^{-}$ is correct.

(c)$N{e}^{+}$ is very unstable and tend to accept one electron willingly. EA of $N{e}^{+}<F$ is incorrect.

(d) $F^{-}$ do not accept additional electron as the electron goes to the new shell. The EA of $F>F^{-}$ is correct.

Hence, two orders are correct in the given options.