Final answer:
Krypton (Kr) would have the closest chemical and physical properties to those of Argon (Ar) as both are noble gases with full valence electron shells, which makes them stable and unreactive. Other options belong to different groups and have distinct properties.
Step-by-step explanation:
The chemical and physical properties of an element are closely related to its position in the periodic table. Argon (Ar) is a noble gas found in Group 18, which is known for elements having full valence electron shells, making them very stable and unreactive. Among the options provided, Krypton (Kr) would have the closest chemical and physical properties to Argon as it is also a noble gas, just one period below Argon in the periodic table. Hence, Krypton also has its energy orbitals full, and as a noble gas, it exhibits similar nonreactivity. In contrast, Chlorine (Cl), Iron (Fe), and Sulfur (S) each belong to different groups and classes of elements (halogen, transition metal, and nonmetal respectively) with distinct properties. Most notably, Chlorine is a halogen which means it is highly reactive, Iron is a metallic element with different states of oxidation, and Sulfur is a nonmetal that is commonly found in various allotropic forms.