chem modelsofparticulatenatureofmatter

Structure 1.4.1 - the mole (mol) is the SI unit of amount of substance, it is used for counting entities. one mole contains exactly the number of elementary entities given by the Avogadro constant

avogadro’s constant is
the avogadro number is

the term elementary entity is used to cover the broad range of possible particles. an elementary entity might be an atom, a molecule, an ion, an electron, any other particle or a specified group of particles