Would ionic or covalent molecules use the molecular formula Why?

Answer 1

Covalently bonded compounds are characterized by a molecular formula, because such compounds exist in the form of discrete molecules, all of the atoms of which move together as kinetic-molecular units. Ionically bonded compounds do not have molecules in this sense: Their compounds are made up of at least two kinds of ions, one positive and the other negative, and the ions in these compounds can move separately as kinetic-molecular units: If a positive ion is separated from the particular negative ion with which it was most closely associated initially in a fluid mixture, usually a solution in an ionizing solvent, of both kinds of ions, another negative ion with the same properties is always close by.