Question

Of these nonmetals, which one is likely to be the least reactive?

oxygen (O)
sulfur (S)
chlorine (Cl)
fluorine (F)

Answer 1

Sulfur (S). Nonmetal reactivity generally increases up the group and to the right; halogens (F, Cl) are very reactive and oxygen is more reactive than sulfur. Sulfur is larger and less electronegative, so it’s the least reactive of the four.