8.3. Metals and Metallic Bonds http://www.ck12.org
metals have been valued for millennia. In this lesson, we are going to investigate a few properties of metals and the
chemical reasons behind some of these characteristics.
Properties of Metals
Physical Properties
Most pure metals share a number of physical properties. Metals are good conductors of electricity and heat. They are
alsomalleable, which means that they can be stamped, pressed, or rolled into thin sheets. For example, aluminum
foil can be made into sheets that are only 13μm thick, and gold (the most malleable pure metal) can be hammered so
thin that it is practically transparent. Metals also tend to beductile, which means that they can be stretched, bent, or
twisted without breaking. The copper wire shown inFigure8.10 is an example of this. Both of these properties are
facets oftoughness, which is a term that describes the ability of a material to withstand shock and to be deformed
without rupturing.
FIGURE 8.10
This image shows a variety of different
copper wires. Copper is a commonly
used substance for wire because it is
highly conductive and ductile but also very
abundant (and therefore inexpensive).Pure metals tend to be shiny in appearance; this property is referred to asluster. Due to our everyday experiences,
we may think of metals as being mostly dull gray in color. However, this is due not to the pure metal but to a surface
layer in which the pure metal has formed an ionic compound, usually with oxygen atoms from either air or water.
Most pure metals are silver-white, but some of the heavier ones (most notably, gold) take on a yellowish hue.
Chemical Properties
We have already discussed some of the chemical properties of pure metals. They have just a few valence electrons
(generally 1-3), which tend to be fairly easy to remove due to metals low ionization energy and electronegativity
values. As a result, they frequently form ionic compounds by transferring their valence electrons to nonmetallic
atoms, which use these extra electrons to complete their valence shells and achieve noble gas configurations.
The driving force to combine with nonmetals to create ionic compounds varies quite a bit between different metals.
Some pure metals, like cesium and potassium, are so eager to react that they must be stored under oil to avoid an
immediate reaction with the oxygen present in air. Others, like platinum and gold, are stable enough that they can
be found in nature as pure metals rather than as the cationic portion of an ionic compound. Gradual degradation of a