The atomic weight, A, is the mass in grams of one mole of atoms of the element The atomic weight, A, is the mass in grams of one mole of atoms of the element A mole is like a dozen, only bigger A mole is like a dozen, only bigger X items per mole X items per mole So a mole of <PERSON> has a mass of grams So a mole of <PERSON> has a mass of grams When rounded to the nearest whole number, it can tell you the average number of neutrons by abundance* When rounded to the nearest whole number, it can tell you the average number of neutrons by abundance* *hang on