simple ionic compounds

Simple Ionic Compounds

Lewis electron-dot symbols together with the noble gas rule can be used to predict the kinds of ions that emerge from the elements - "monatomic" ions. The idea is that elements will tend to gain or loose electrons in such a way that they will have an octet (eight) valence electrons leaving a lewis dot symbol with 8 electrons around it. This rule applies to the alkali, alkali earth and main group elements. It obviously does not apply to H, He, Li, Be, and B since these elements have too few electrons to consider octets. In these latter cases the helium noble gas configuration applies.

Examples of Simple Ions

In the above diagram, when Li, Be and Ca loose their electrons the "new" valence electrons in the ion are drawn in. These elemental ions are stable in the sense that they will not readily gain or loose electrons. However, since they are charged they can combine electrostatically to form ionic bonds. the resulting compound is called "ionic" or "salt", e.g., Ca+ + 2Cl- ---> Ca(Cl)2 = calcium chloride.

C101 Class Notes