Unit #1Unit #2Unit #3Unit #4Unit #5Unit #6Unit #7Unit #8Unit #9Unit #10
spacerUNIT # 5  

spacer5.1 Ionic

spacerIonic Bonding in Sodium Chloride
spacerIonic Bonding in Magnesium Chloride
spacerProperties of Ionic Compounds
spacer5.2 Covalent
spacer5.3 Polar Covalent

spacer5.4 Bond

spacer5.5 Electroneg-

spacer5.6 Classification
spacerof Bond Type
spacer5.7 Polarity of
spacer5.8 Writing
spacerWriting formulas containing simple ions
spacerWriting formulas containing  polyatomic ions
spacerUsing parentheses in formula writing
spacer5.9 Information in
spacera Chemical
spacerNumber ratio of atoms
spacerNumber ratio of ions
spacer5.10 Oxidation
spacerAssignment of Oxidation Numbers

spacer1 | 2


5.1 -
Ionic Bonding

5.1.2 - Ionic Bonding in Magnesium Chloride

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:

  1. 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.

  2. 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
The Ionic Bond ..p124


All contents copyrighted © 1996-2006
British Columbia Institute of Technology
Chemistry Department - 3700 Willingdon Avenue
Burnaby, B.C. Canada V5G 3H2