Which property is common to metalloids?

Metalloids are unique elements that exhibit properties intermediate between metals and nonmetals. The characteristic of having a metallic appearance while also being somewhat brittle is a defining feature of metalloids. Unlike true metals, which are typically malleable and ductile, metalloids retain a shiny, metallic luster but are not as flexible and can break or shatter when subjected to stress.

This metallic appearance makes them visually similar to metals, contributing to the reason why they are often grouped with metals in the periodic table. However, their brittleness distinguishes them from typical metals, which tend to deform under stress rather than break. Therefore, recognizing this unique combination of properties helps in identifying and understanding metalloids in the study of atomic theory and materials science.