What is a common characteristic of nonmetals?

Nonmetals are indeed characterized by typically having lower melting points when compared to metals. This is mainly due to the differences in bonding and structure between the two classes of elements. Nonmetals often form covalent bonds, resulting in molecular structures that require less energy to break apart, leading to lower melting and boiling points. In contrast, metals usually consist of closely packed atoms with metallic bonding, which generally has higher melting points because of the strong interactions between the positively charged metal ions and the delocalized electrons.

The other options do not align with nonmetal characteristics. Nonmetals are usually poor conductors of electricity, as they lack free-moving electrons that are essential for conductivity. While some nonmetals can react with metals, they do not typically do so aggressively and the nature of the reactions can vary significantly based on the nonmetal involved. Lastly, nonmetals are not known for ductility, a property that describes the ability of materials to deform under tensile stress, which is a trait characteristic of metals. Thus, the common aspect that nonmetals usually have lower melting points is a defining feature of this group.