Some compounds that dissolve forming ions form a lot of ions while others form just a few. You can change their chemical form . Some substances remain soluble or not soluble regardless of what you do. You can make generalities about solubility behavior that helps you create a classification scheme. Chemical substances that are pure are uniformly one thing.
Pure substances are either elements or compounds, two or more elements combined in unique ways.
Compounds are represented by a formula and a distinctive name. It is an ionic compound. An ionic compound has two words in its name. Sucrose is a molecular compound. Of course there is more to ionic compounds than having two names.