The Reaction between Magnesium and Oxygen
Consider another example of ionic bond formation is the reaction between magnesium and oxygen forming magnesium oxide. Magnesium is in group-ll of the periodic table and has only two electrons to share and oxygen is in group VIA and has six electrons in its outermost shell. By losing two electrons from the outermost shell, magnesium becomes Mg and it is left with 8 electrons in the second shell. By gaining two electrons, oxygen 2+ atom now also has eight electrons in its outermost shell and becomes O.Both these atoms are now changed into oppositely charged ions. The attraction between the oppositely charged ions forms the ionic bond between magnesium and oxygen. The formula of magnesium oxide is MgO. The formation of ionic bonds by a 'dot and cross diagram is shown in figure 4.3.
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| The Reaction between Magnesium and Oxygen |
The ionic bond between magnesium and oxygen is stronger than the ionic bond between sodium and Chlorine because of the greater charge on the ions. Magnesium oxide has higher melting point due to the presence of the stronger bond.
