The correct statement is:
Metals can be hammered into thin sheets, and nonmetals are brittle.
Metals are malleable (meaning they can be hammered into thin sheets) and ductile, while nonmetals tend to be brittle in solid form.
The other statements are incorrect because:
- Metals are generally good conductors of electricity, while many nonmetals are poor conductors (insulators).
- Most metals are solids at room temperature, while most nonmetals are gases; only bromine is a liquid under normal conditions.
- Not all columns of the periodic table contain both metals and nonmetals; for example, the noble gases column contains only nonmetals.