Which group of elements has properties intermediate between metals and nonmetals?

• A. Metals
• B. Nonmetals
• C. Metalloids
• D. Covalent

Answer: (C)

Metalloids are elements that show mixed traits of metals and nonmetals, sitting on the boundary between the two kinds. They often have a metallic shine like metals but are brittle like nonmetals, and they behave as semiconductors—conducting electricity better than nonmetals but not as well as metals. This conductivity can be tuned by temperature or by adding impurities, which is a hallmark of their intermediate nature. Their chemistry is typically covalent, reflecting their intermediate electronegativity, rather than the highly ionic or metallic bonding seen in pure metals or the simple nonmetal behavior. Examples such as silicon and germanium illustrate this blend: they’re not as conductive as metals, yet they’re not as insulative as typical nonmetals. Because these elements consistently straddle the line between metal and nonmetal properties, they’re the group that fits the description of having intermediate characteristics.