• # question_answer 57)   Among halogens, the correct order of amount of energy released in electron gain (electron gain enthalpy) is: (a) $F>Cl>Br>I$              (b) $F<Cl<Br<I$              (c) $F<Cl>Br>I$               (d) $F<Cl<Br>I$

(c) Chlorine has higher electron gain enthalpy than fluorine. This is due to small size of fluorine atom, i.e., the electron density is high which resists the addition of an electron $\left( \text{F Cl} \right)$. In general, electron gain enthalpy decreases as atomic size increases. Thus, $Cl\text{ }>\text{ }Br\text{ }>\text{ }I$