Low conductivity, not ductile, not malleable, brittle, dull, gas at room temp.

• A. Non-metals
• B. Metals
• C. Metalloids
• D. Noble gases

Answer: (A)

The key idea is how materials are classified by their properties. Metals are generally shiny, have high electrical conductivity, and are malleable and ductile. Non-metals, on the other hand, tend to have low electrical conductivity, are not ductile or malleable, and many solids are brittle and dull; some non-metals are gases at room temperature. The description—low conductivity, not ductile, not malleable, brittle, dull, and a gas at room temperature—fits non-metals best because it matches the broad pattern of non-metal behavior across different states. Metals don’t fit due to their conductivity and malleability, while metalloids vary and noble gases, though gases at room temperature, are not described as brittle solids.