Question

Electron gain enthalpy with negative sign of fluorine is less than that of chlorine due to :

• A. High ionization enthalpy of fluorine
• B. Smaller size of chlorine atom
• C. Smaller size of fluorine atom
• D. Bigger size of $2p$ orbital of fluorine

Answer 1

Answer: (C)

Smaller size of fluorine atom

Answer 2

The electron gain enthalpy order for halogens is
$CI > F > Br > I$
Due to small size of fluorine the extra electron to be added feels more electron- electron repulsion. Therefore fluorine has less value for electron affinity than chlorine.