Why aren't the atomic masses of most elements whole numbers

Isotopes and most average aren't whole numbers

False, as a substance changes from a solid to a liquid and from a liquid to a gas the molecules get farther apart from each other

Hello thereone of the following properties was originally used to arrange elements on the periodic table, but is no longer used to organize the modern version. which property fits this description? answer: atomic mass  was originally used to arrange elements on the periodic table, but is no longer used to organize the modern version.