Metals, Nonmetals, and Semimetals
All elements can be classified as being a metal, nonmetal, or semimetal (also
referred to as a metalloid). Let’s start by talking about metals. Metals share
certain physical characteristics. They are usually shiny and are good conductors
of heat and electricity. Many metals are malleable, which means they can be
hammered into thin sheets such as aluminum foil. Metals are also often ductile,
which means that they can form wires. (Copper, for example, is ductile.) With
the exception of mercury (a liquid), all metals are solid at room temperature.
While these characteristics are noteworthy, there is one chemical characteristic
that, above all else, makes an element a metal. Metals tend to give up electrons
when they bond.
Transition Metals
Roughly 75 percent of the elements are considered to be metals, and metals
can be further divided into active and transition metals. The reactive
metals of the s area are classified as active, while the rest are classified as
transition metals. Transition metals are quite different from active metals.
They are generally harder, more difficult to melt, and less reactive than
active metals. Transition metals include those elements in the d and f areas.
Many of the elements that come to mind when we think of metals are
transition metals such as iron, copper, gold, and silver. Many compounds
that contain a transition metal are intensely colored. For instance, many
copper compounds (but not the element itself) are blue.Nonmetals are elements that tend to gain or share electrons when they bond.
This distinguishes them from metals. Nonmetals are usually poor conductors of
heat and electricity, and some such as sulfur (S) and phosphorus (P) are solids at
room temperature. Unlike metals, they are dull, brittle, and melt easily (although
diamond, which is composed of the nonmetal carbon, is an exception to these
rules). A few nonmetals, such as oxygen (O) and fluorine (F), are gases. The
nonmetal bromine (Br) is a liquid at room temperature. As you can see, the
physical properties of nonmetals vary considerably.
Semimetals, or metalloids, have some of the physical characteristics of both