The Greek philosopher Democritus first used the term ‘ atomos’, meaning ‘uncuttable’, to describe the tiny, unbreakable objects that he suggested made up all matter in the universe.Īntoine Lavoisier’s law of conservation of matter stated that in any system that is closed to the transfer of matter – both in and out – the amount of matter is conserved. Unknown to western scientists in Dalton’s time, an Indian philosopher’s son called Acharya Kanada first conceptualised the idea of indivisible matter (the ‘ anu’) around 2,500 years earlier - after breaking the food in his hand into smaller and smaller pieces until he was left with just its smell. Dalton’s breakthrough was heavily influenced by the work of French scientists Antoine Lavoisier (1743-1794) and Joseph Proust (1754-1826), but some philosophers were exploring the concept long before that: “Many chemists found themselves using atomic theory,” Marc Michalovic writes, “even if they held their noses all the while.”Īlthough Dalton is regarded as the first proponent of modern atomic theory, the idea that matter is comprised of minute particles has a long and brilliant – although not always acknowledged – history. However, whether proven or not, atomic theory proved useful because it was simpler to express the stoichiometry of a chemical reaction in atoms rather than absolute mass, while organic chemistry in particular made rapid advances once Dalton’s ideas were accepted.

Amongst those who remained unconvinced were Sir Humphry Davy (1778-1829) and the leading French chemist, Claude-Louis Berthollet (1748-1822). For many scientists, the fact that he could not confirm it by direct observation – because atoms could not be seen – was problematic. Of course, Dalton’s atomic theory was not without its flaws – and its critics. “And from that day to this, chemistry’s been done on that basis.” “For the first time ever, we’ve suddenly got a language, a way of thinking about it, a set of formulae that advance chemistry tremendously,” Thackray says. In the book, Dalton also drew individual atoms and compound atoms for the first time – a breakthrough that still forms the basis of how chemists visualise elements and molecules today, as well as the notation that they use. The atom is the smallest unit of matter that can take part in a chemical reaction. In chemical reactions, atoms are combined, separated or rearranged.Ħ. Atoms of the same element can combine in more than one ratio.ĥ. Atoms of different elements can combine in fixed, whole number ratios to form compounds.Ĥ. Atoms cannot be subdivided, created or destroyed.ģ. Atoms of the same element are similar in shape and mass, but differ from the atoms of other elements.Ģ. The self-taught Dalton, who came to chemistry by way of meteorological observations in his rain-swept, native Cumberland, also gave the world several more big ideas that together made up his atomic theory:ġ. The writer was John Dalton – born 255 years ago today, on Septem– and his 1808 work, New System of Chemical Philosophy, was about to usher chemistry into the modern age.ĭalton’s work first established what science historian Arnold Thackray says is now “ one of the most familiar ideas in the world” - that all matter is made up of tiny, indivisible particles called atoms. His intention, he wrote, was “to place the whole science of Chemistry upon a new, and more simple, basis than it has been upon heretofore,” and it’s safe to say this wasn’t just hyperbole. More than 200 years ago, a teacher from the North West of England was drafting a leaflet to publicise his new science book.

John Dalton – the Father of Modern Chemistry

Process materials, geological, cement and soils.

Standards for environmental regulatory methods.

Polycyclic aromatic hydrocarbons (PAHs).

Enzyme activators, inhibitors & substrates.

Father of atomic theory