Here are the standard reduction potentials of all the halogens:
$F _2 \rightarrow 2.87$
$Cl _2 \rightarrow 1.36$
$Br _2 \rightarrow 1.07$
$I _2 \rightarrow 0.54$
$F _2$ has high hydration energy and low bond dissociation energy of all and that is why it is the strongest oxidizing agent of all.