|Value of NA in various units|
The Avogadro constant (symbols: L, NA) is the number of particles (usually atoms or molecules) in one mole of a given substance. Its value is equal to 6.02214129(27)×1023 mol−1. The constant was named after the Italian scientist Amedeo Avogadro.
The measurement of Avogadro's constant was refined in 2011 to 6.02214078×1023 ± 1.8E-7×1023.
An old term closely related to the Avogadro constant is Avogadro's number. Avogadro's number is the number of atoms in 12 grams of the carbon isotope carbon-12. Avogadro's number is a dimensionless quantity and has the numerical value of the Avogadro constant given in base units.
Images for kids
Ball-and-stick model of the unit cell of silicon. X-ray diffraction measures the cell parameter, a, which is used to calculate a value for Avogadro's constant.
Avogadro constant Facts for Kids. Kiddle Encyclopedia.