Question

Which of the two F , Cl have higher negative electron gain enthalpy

Answer 1

Chlorine (Cl) has morenegativeelectron gain enthalpy than fluorine (F). F has less negative electron gain enthalpy because in it the addedelectron goes to the smaller energy level (n=2) and hence suffers significant repulsion from theelectrons already present in this shell.
OR


The size of fluorine atom is small. As a result, there are strong electron-electron repulsions in the compact 2p-orbital. Thus, the electron gain enthalpy of fluorine is less negative than that of chlorine.

Answer 2

Cl has most -ve electron gain enthalpy in periodic table . According to periodicity F should have most -ve electron gain enthalpy , but as the size of F is too small and it has no d orbital, electrons are closely packed which do not allow further addition of electron due to repulsive forces. Cl as larger size than F and presence of d orbitals the electrons are far from each other which makes further addition of electron easier .


Hope it helps u dude