Which category includes elements that are poor conductors of heat and electricity and tend to gain electrons to form anions?

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

Answer: (B)

The essential idea is that the properties described—poor conductors of heat and electricity and a tendency to gain electrons to form anions—are characteristic of nonmetals. Nonmetals have higher electronegativity and electron affinity, so they attract and accept electrons readily, forming negative ions in compounds. They lack the delocalized electrons that allow metals to conduct well, which is why they are poor conductors. Metalloids show mixed properties, not a clear match to both traits. Covalent refers to a type of bond, not a category of elements, so it doesn’t describe the elements’ conductivity or ion-formation behavior. Thus, nonmetals fit best.