1 mole of a substance equals the amount of grams needed for that substance to have 6.0221413e+23 (Avogadro's number) atoms in it, isn't it? In order to determine how many grams one mole of a substance is, I've learned that you just need to check the atomic mass number on your periodic table, take that number and put "gram" at the end. The thing I don't understand is, how come it's that simple? The atomic mass number is the number of protons and electrons (nucleons) in the atom, right? So how come 6.0221413e+23 times the mass of all nucleons ALWAYS amounts to the number of nucleons in grams for any substance? For example, carbon has an atomic mass number of 12 so 1 mole of carbon equals 12 grams of carbon. Hydrogen has an atomic mass number of 1 so 1 mole of carbon equals 1 gram of hydrogen. Is this some great coincidence? Or is there a link that I'm not seeing? I'm not sure I understood what a mole is and my research on it just confuses me, so there's why I'm asking. Thank you for reading and (hopefully) helping!