What does the mass number on the periodic table mean?
NOTE: (don’t be confused by the periodic table) Different elements have isotopes with varying mass numbers, so the mass number displayed on a periodic table is the ratio of those isotopic mass numbers in any given sample of the element your examining. This ratio is often confused with with the mass number of the element when it is displayed on periodic tables, it is actually the relative atomic mass. You can tell if a number is the mass number or a relative atomic mass by whether or not it is a whole number if it is then it’s a mass number if it has decimal places out beside it then you’re looking at relative atomic mass.
