Explain why fluorine forms only one oxoacid, HOF.

Explanation

Chlorine , bromine and iodine form four series of oxyacids of the general formula HOX, HOXO , `HOXO_2` and `HOXO_3` in which the oxidation states of halogen (X=Cl , Br or I) is +1, +3 , and +5 and +7 respectively. However , due to high electronegativity , small size and absence of d-orbitals , F cannot act as central atom in higher oxacids such as HOFO , `HOFO_2` and `HOFO_3` In which the oxidation state of F would be +3 , +5 , +7 . It justs forms one oxoacid. i.e., HOF in which the oxidation state of F is -1 and oxygen is in +1.