But what about chlorine? Having gained an electron, chlorine also ends up with
8 electrons in its outermost shell. Its electron configuration looks like argon’s.
The bond that results creates sodium chloride: NaCl. The attraction between a
positive charge and a negative charge is called an electrostatic force; this force
is very strong. The strength of an ionic bond gives ionic compounds their high
melting points, hardness, and other physical properties.
Substances that are
held together by ionic
bonds are solids at room
temperature and atmospheric
pressure. Ionic
solids are characterized by
their hardness, brittleness,
and high melting points.
Although ions are charge
carriers, ionic solids cannot
conduct electricity
because their ions have
very restricted movement.
However, if an ionic
solid is melted, its ions are
freer to move,
and the substance can
conduct electricity.For this test, think as follows:
When a metal and nonmetal bond, the result is an ionic bond, in which
the atoms are held together by an electrostatic attraction between a
positive and a negative ion.Ionic Formulas
It is possible to use the Periodic Table to predict the charges of many common
ions. As we discussed in Chapter 6, elements are most stable when they have a
full valence octet. So, a neutral atom will either gain or lose sufficient electrons
to create an ion that has a full octet, no more and no less.
Let’s take sulfur as an example. Sulfur has six valence electrons, and can either
gain two electrons to fill the third energy shell, or lose six electrons to leave
behind a full second energy shell. It is easier for a sulfur atom to gain two