Discussion on Periodic Classification Of Elements

 The mole is a unit of measurement used in chemistry to express amounts of a chemical substance, defined as an amount of a substance that contains as many elementary entities (e.g., atoms, molecules, ions, electrons) as there are atoms in 12 grams of pure carbon-12 (12C), the isotope of carbon with atomic weight 12. This corresponds to a value of 6.02214179(30)×10^23 elementary entities of that substance. It is one of the base units in the International System of Units, and has the unit symbol mol.