The oxidizing character of elements increases from left to right across a period. Thus, we get the decreasing order of oxidizing property as `F gt O gt N`.
Again, the oxidizing character of elements decreases down a group. Thus, we get `F gt Cl.`
However, the oxidizing character of O is more than that of Cl i.e., `O gt Cl.`
Hence, the correct order of chemical reactivity of F, Cl, O, and N in terms of their oxidizing property is `F gt O gt Cl gt N`.
