Nonmetal: definition in chemistry
Nonmetal: An element that lacks the properties of metals: nonmetals are usually poor conductors of heat and electricity, and their solids are dull and brittle.
Nonmetals tend to gain or share electrons rather than lose them, so they form negative ions with metals and covalent bonds with each other. Many are gases at room temperature, such as oxygen, nitrogen and the noble gases, while bromine is a liquid and carbon, phosphorus, sulfur and iodine are solids. Although fewer than 20 elements are nonmetals, they make up most of the mass of living things.
Examples
- Oxygen — a gas that makes up about 21% of air
- Sulfur — a brittle yellow solid
- Bromine — the only nonmetal that is liquid at room temperature
- Graphite — an unusual form of carbon that conducts electricity
On the periodic table
Nonmetals sit at the upper right of the table, to the right of the zigzag line of metalloids, with hydrogen as the exception at the top left.