The reactivity of a nonmetal depends on how much it wants an electron (or more) in order to fill its valence shell (to octet) AND how small it is. Argon is smaller than chlorine, but chemically, it's not anything. It's a nonmetal in a physical sense. Within a family, nonmetals are more active as the nonmetal gets smaller (because the electrons are closer to the nucleus). F is the most active nonmetal: It is the smallest nonmetal just short of an octet (with the exception of hydrogen, which is a special case and generally loses electrons rather than gains them.
Shelly G.
Hi! Thanks for answering. So you’re saying that the smaller the atomic radius is, the more reactive the atom will be because the electrons are closer to the nucleus. But I thought sulfur was more reactive than argon because argon is a noble gas, and doesn’t need to be reactive as it has 8 valance electrons. I also know that sulfur is bigger than argon, and is more reactive.10/06/20