[BushBond]

So while I was studying I got curious on leaving groups in aromatic rings, as I was reading I was a little bit sceptical about the data, why? Why is fluorine better leaving group than Iodine, shouldn't it be the opposite I mean the orbital overlapping of Fluorine-Carbon is much better than Iodine-C, yet according to data Fluorine leaves in a much easier way, he is a hungry electrophile, an aromatic ring is full of electrons…

The nuclear effective charge is the highest also the electronegativity.

Please guys help me understand it has been a while since I took Inorganic, but I should at least have the proper intuition into this

[OrganicDan96]

i assume you are talking about aromatic substitution type reactions, it is correct that fluorine is better than iodine but it isn't to do with leaving group ability, there is another factor at play here, do you know what it might be?

[BlitzHypercharge]

Flourine is a better leaving group only in nucleophilic aromatic substitutions.You may want to refer the mechanism

[hollytara]

Having done these reactions it definitely is true: F>Cl>Br>I

If you think about the steps and what is rate determning it makes sense.