An element that is generally a poor conductor of heat and electricity is known as a ______
superconductor
magnet
alloy
nonmetal
A nonmetal is an element that is generally a poor conductor of heat and electricity. Many properties of nonmetals are the opposite of those seen in metals. There is a wider variation in properties among the nonmetals than among the metals, as seen in Figure below . Nonmetals exist in all three states of matter at room temperature. The majority are gases, such as nitrogen and oxygen. Bromine is a liquid, and a few are solids, such as carbon and sulfur. In the solid state, nonmetals are brittle, meaning that they will shatter if struck with a hammer. The solids are not lustrous, and their melting points are generally much lower than those of metals. On the periodic table in the Figure above , the nonmetals are shaded green and appear to the right of the stair-step line.