Using the ideas from this section and the periodic table, choose the more reactive nonmetal. f or cl

F  

Step-by-step explanation:

The halogens are in Group 17, so they all need one electron to complete their octet.

As you go up a Group, the atoms get smaller.

Their electronegativities are measures of how badly the atoms "want" that extra electron, and they increase as you go up the Group.

The higher the electronegativity, the more reactive the element will be as it tries to grab that extra electron.

Fluorine is at top of the group, so it is the most reactive element.

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.