There are many compounds which have ionic bonds. They are called
ionic compounds, and they are formed when metals
react with nonmetals.
In section 5.1.1 we saw an example of an
ionic compound.
Let's examine another ionic compound, one that doesn't have a
1:1 metal ion to nonmetal ion ratio. We'll use Lewis Electron Dot Symbols to
describe the ionic bonding that is observed in magnesium chloride. The formation
of magnesium chloride can be thought of as a result from a reaction involving
magnesium
metal, Mg and chlorine
gas, Cl2. The reaction can be thought of involving the following
simultaneous processes:
The Oxidation of Magnesium Metal
Recall from section
4.6, a magnesium atom loses its 2 outer-shell
electron to become a magnesium ion, (i.e. cation).
The magnesium metal is said to be oxidized.
The Reduction of Chlorine Gas
Recall from section 4.7,
chlorine is a diatomic element. The covalently bonded Cl2 molecule
gains two electrons to become two chloride ions,
(i.e. anions).
Chlorine is said to be reduced.
Combining the above oxidation and reduction processess, the overall effect
is the transfer of TWO electrons from magnesium
to chlorine.
The oppositely charged of the magnesium and chloride ions attract
each other and ionic bonds are formed. In the
solid state, each cation is surrounded by anions, and each anion is surrounded
by cations. The simplest ratio of Mg+2 : Cl- is 1:2. The
simplest formula for this ionic compound is MgCl2.
Section 6.4 
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