Amedeo Avogadro an Italian scholar. He is most noted for his contribution to molecular theory, including the Avogadro's law. In tribute to him the number of elementary entities, ( atom, molecules, ions or other particles. ) In 1 mol of a substance 6.022 x 10²³ is known as Avogadro number.
1) In 1811, he published article in French journal on determining the relative masses of the elementary particles of bodies and proportions by which they enter combinations.
2) In 1821, he published a research paper titled " New considerations on the theory of proportions and on determination of masses of atoms".
3) In 1841, he published his work in 4 volumes. Four years after his death, scientific community could understand importance of his work.
Avogadro's work was brought into light after his death by Cannizzaro in the year 1858. It was only in 1911, Avogadro's contribution to chemistry was recognised.