Reaction intermediates differ from activated complexes in that:
a. they are stable molecules with normal bonds and are frequently isolate.
b. they are molecules with normal bonds rather than partial bonds and can occasionally be isolate.
c. they are intermediate with have characteristics of both reactants and products.
d. they are unstable and can never be isolated.
e. all reactions involve reaction intermediates, but not all have activated complexes.

the seeing the electronic configuration we can say that the element is fluorine.

fluorine is the most electronegative element in the periodic table.

but by only seeing the configuration we cannot say about its reactivity because we don't know if its configuration after excitation or by addition of electrons.

but if not then, it is the lightest halogen and exists as a highly toxic pale yellow diatomic gas at standard conditions. as the most electronegative element, it is extremely reactive: almost all other elements, including some noble gases, form compounds with fluorine.