How do you find the roman numeral in binary AND ionic compounds?

In naming the transition metal ion, add a Roman numeral in parenthesis after the name of the transition metal ion. The Roman numeral must have the same value as the charge of the ion. In our example, the transition metal ion Fe2+ would have the name iron(II). Add the name of the anion to the transition metal ion.

Explanation:

it is b that is the answer.

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.