D. Download the zipped version of the first installments of this series, originally published in the Sci-Tech Translation Journal, of the American Translators Association. We learned in the chapter on covalent bonds that such bonds consist of one or more electron pairs, and that when such an electron pair splits symmetrically, free radicals are formed, each free radical having an unpaired electron. In such an event, two ions are formed, a negative alkoxide ion and a positive hydrogen ion. Even without being broken, some covalent bonds between dissimilar atoms are polar , which means that one partner in the bond holds more tightly to the electrons than the other, or is more electronegative than the other. If and when such a polar bond splits, the electronegative partner is most likely to depart with both of the electrons and become an ion.
Water is strongly polar and has great affinity for ions.
It tends to form shells around ions and is held to them by coordinate bonds or hydrogen bonds . These are loose bonds of a polar nature, but are not covalent bonds in the usual sense of the word. When ionic substances dissolve in water, their ions become hydrated in this way. Nonionic and nonpolar substances tend to be insoluble or only slightly soluble in water because there is no energy of hydration to drive them into solution. If nonpolar substances are present also, they are attracted to the lipophilic portions of the micelles, and are suspended in the aqueous phase by this attraction.