The approximate value of the Avogadro constant is 6.022 × 10^23 particles per mole. It tells scientists how many specified entities—such as atoms, molecules, ions, or other particles—are contained in one mole.
The mole is the SI unit for amount of substance, allowing chemists to connect microscopic particles with measurable laboratory quantities. One mole of carbon-12 atoms, for example, contains approximately this enormous number of atoms. The constant is now defined exactly as 6.02214076 × 10^23 per mole, while 6.022 × 10^23 is the standard rounded form used in quizzes and introductory chemistry.
The number is named after Italian scientist Amedeo Avogadro, although Avogadro did not determine its numerical value. In 1811, he proposed that equal volumes of gases at the same temperature and pressure contain equal numbers of molecules, an idea that helped distinguish atoms from molecules.
A common mistake is reversing the exponent. The value is 10^23, not 10^-23: it is an extremely large count. Another mix-up is the elementary charge, approximately 1.602 × 10^-19 coulomb, which is a different physical constant entirely.