Final answer:
The compound XCl is classified as ionic if X represents the element Rb (Rubidium), as it is a metal from Group 1 that forms an ionic compound with chlorine, a nonmetal from the halogen group.
Step-by-step explanation:
The compound XCl is classified as ionic if X represents the element Rb (Rubidium). This is because Rubidium is a metal from Group 1 elements, which all tend to form halogen compounds with a 1:1 ratio due to their single valence electron. They readily lose this electron to achieve a noble gas electron configuration, forming cations. Halogens, like chlorine (Cl), have seven valence electrons and readily gain one electron to achieve a noble gas electron configuration, forming anions. When these two types of elements combine, they form ionic compounds due to the electrostatic attraction between the positively charged metal cation and the negatively charged nonmetal anion.
The halogen element Iodine (I), Bromine (Br), and Hydrogen (H), would not result in an ionic compound when paired with chlorine since they are nonmetals and would instead likely share electrons to form covalent bonds.