What characterizes an ionic bond?

An ionic bond is characterized by the transfer of electrons from one atom to another. This typically occurs between metals and nonmetals, where the metal atom relinquishes one or more electrons to achieve a stable electron configuration, usually that of a noble gas. In turn, the nonmetal atom gains these electrons to fill its outer shell. The result of this transfer is the formation of ions: positively charged cations (from the metal) and negatively charged anions (from the nonmetal). These oppositely charged ions attract each other, resulting in a strong electrostatic force that defines the ionic bond.

The other choices reflect different types of bonding or states of matter that do not pertain to the fundamental nature of ionic bonds. For instance, the sharing of electrons pertains to covalent bonds, while the formation of molecules often involves covalent interactions as well. The liquid state at room temperature is not a characteristic of ionic compounds, which are typically solid at room temperature due to their strong ionic bonds.