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.