[BeepoGirl]

Bond enthalpies for dihalogens decrease down the group as the atomic radius decreases and electrons are less attracted, except for F₂.

I understand this was because of all the lone pairs it has in a very small space making the electron density high, however I was told that there is a much better explanation for this, what is it?

[nj_bartel]

It's my understanding that F₂ actually binds through a p-orbital.