Final answer:
Argon is the least reactive element among those listed because it is a noble gas with full energy orbitals, making it chemically stable and unreactive.
Step-by-step explanation:
Among the elements listed — fluorine, argon, iodine, and silver — argon is the least reactive element. Argon is a noble gas, which means it has a complete set of electrons in its outermost energy level (full energy orbitals), making it very stable and unreactive.
Argon's lack of reactivity contrasts with the other elements listed: fluorine, which is the most reactive halogen; iodine, which is a less reactive halogen; and silver, which is a transition metal that can still partake in chemical reactions.
Referring to the provided information for clarification:
- Fluorine is part of the halogen group and is a highly reactive nonmetal.
- Iodine is also a halogen, but it is the least reactive of the halogens and does not oxidize other halide ions.
- Argon, being a noble gas, has all its energy orbitals full and is the least likely to react chemically.