2019International Year of the Periodic Table - Set

The concept of the atom (from the Greek word meaning indivisible) introduced by Democritus (ca. 460 B.C. - ca. 370 B.C.) is perhapsone of the most brilliant scienti c ideas in the history of mankind.Despite the fact that the atom is quite an ancient concept and that chemistry has a central place within the pure sciences, its development is very recent (the last 250 years). As a modern science, we can associate its birth with the publication of the Lavoisier treatise in 1785. The notion of an elementary substance (which cannot be divided into others with lower mass) would open a new, quantitative era in chemistry. In Portugal, the development of chemistry was promoted by the Pombaline reforms to the university system, which introduced the teaching of chemistry and led to the creation of the Chymico Laboratory (inaugurated in 1775/76) at the University of Coimbra.