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. For example, sodium chloride, NaCl, is an ionic compound.
Magnesium chloride is another ionic compound. Unlike sodium chlorid, this compound does not have a 1:1 metal ion to nonmetal ion ratio. Lewis Electron Dot Symbols can be used to describe the ionic bonding in magnesium chloride.
Lewis electron dot symbol to describe ionic bonding in magnesium chloride
The formation of magnesium chloride can be thought of as a reaction involving magnesium metal, Mg, and chlorine gas, Cl2. The reaction can be thought of as involving the following simultaneous processes:
- The Oxidation of Magnesium Metal
Recall from the Octet rule, a magnesium atom, which is a metal in Group II A, tends to lose its 2 outer-shell valence electrons to become a magnesium ion, (i.e. cation). The magnesium metal is said to be oxidized.
- The Reduction of Chlorine Gas
Recall 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 processes, 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.
