Explain what happens to an ionic substance when it dissolves in water. drag the terms on the left to the appropriate blanks on the right to complete the sentences. ionic compounds dissolve in water and dissociate into the ionic compounds dissolve in water and dissociate into the blank that make up the compound. for example, nacl in water will form blank ( a q ) (element of the i group) and blank ( a q ) (element of the vii group). that make up the compound. for example, nacl in water will form ionic compounds dissolve in water and dissociate into the blank that make up the compound. for example, nacl in water will form blank ( a q ) (element of the i group) and blank ( a q ) (element of the vii )(element of the i group) and ionic compounds dissolve in water and dissociate into the blank that make up the compound. for example, nacl in water will form blank ( a q ) (element of the i group) and blank ( a q ) (element of the vii )(element of the vii group).