Which of the following is a common characteristic of metals?

Metals are characterized by several distinct properties, one of which is their shiny appearance and ductility. The shiny or lustrous quality of metals arises from their ability to reflect light due to the structure of their electrons, which allows them to absorb and re-emit light. This property is why metals are often used in decorative applications, as well as in various industrial uses requiring shiny surfaces.

Ductility is another essential feature of metals, allowing them to be stretched into wires without breaking. This property is attributed to the metallic bonding that permits layers of atoms to slide past each other while maintaining the overall structure's integrity. This ability to be drawn into wires is critical for many applications, such as electrical wiring and cable manufacturing.

Understanding these characteristics helps explain why certain materials are classified as metals. Other options, such as brittleness, poor conductivity, and gaseous states at room temperature, do not apply to metals in general and distinguish them from nonmetals or metalloids. These traits make metals unique and valuable in various contexts, including construction, manufacturing, and electronics.