Math the following terms with the correct definition. Column A 1. atom: atom 2. element: element 3. ion: ion 4. mass number: mass number 5. stable: stable Column B a.in atoms, the condition in which a nucleus is unlikely to undergo decay b.a pure substance that cannot be changed into simpler substances through chemical or physical means c.the sum of the protons and neutrons that make up the nucleus of an atom d.the basic unit of a chemical element e.a charged particle that results when the number of protons and number of electrons differ