Amedeo Avogadro Count of Quaregna and Cerreto (9 August 1776, Turin, Piedmont-Sardinia – 9 July 1856), was an Italian scientist. He is most noted for his contribution to molecular theory now known as Avogadro's law, which says equal volumes of gases under the same conditions of temperature and pressure will contain equal numbers of molecules.
A-Amedeo Avogadro. He is most noted for his contributions to molecular theory, including what is known as Avogadro's law. In tribute to him, the number of elementary entities (atoms, molecules, ions or other particles) in 1 mole of a substance is known as the Avogadro constant.