Metals and Nonmetals
In their purest form, most of the chemical elements on the periodic table are classified as metals. But what does that mean? What is the difference between a metal and a nonmetal? Below we explore some of the differences between metals and nonmetals in terms of physical properties and chemical properties.
Physical Properties
One of the most important physical properties of metals is that unlike nonmetals, they are good conductors of heat and electricity. Metals are good conductors because the valence electrons have considerable mobility and this is the property that enables the transfer of heat and electricity. Metals are malleable, whereas solid nonmetals are brittle. Metals, as opposed to nonmetals, are ductile and can be stretched and shaped into a wire. Metals exhibit metallic luster that nonmetals do not. When metals are in the form of a thin sheet, they appear to be opaque. Nonmetals, on the other hand, are transparent in the form of a thin sheet. At room temperature, metals (with the exception of Mercury) exist as solids. Nonmetals, can exist as solids, liquids or gases at room temperature.
Chemical Properties
Metals typically have one to three electrons in their outer shell, whereas nonmetals have four to eight electrons in their outer shell. Metals tend to lose their valence electrons easily, as opposed to nonmetals, which tend to gain or share valence electrons easily. Metals form basic oxides, but nonmetals form acidic oxides. Chemically, metals are good reducing agents (which refers to substances capable of bringing about the reduction of other substances as they themselves are oxidized). Nonmetals, on the other hand, are good oxidizing agents, (which are substances that oxidize other agents by accepting electrons). Finally, metals have lower electronegativities and nonmetals have higher ones. Electronegativity refers to the tendency of an atom or radical to attract electrons in the formation of an ionic bond.