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  2. History of atomic theory - Wikipedia

    en.wikipedia.org/wiki/History_of_atomic_theory

    Dalton defined an atom as being the "ultimate particle" of a chemical substance, and he used the term "compound atom" to refer to "ultimate particles" which contain two or more elements. This is inconsistent with the modern definition, wherein an atom is the basic particle of a chemical element and a molecule is an agglomeration of atoms.

  3. John Dalton - Wikipedia

    en.wikipedia.org/wiki/John_Dalton

    John Dalton FRS (/ ˈ d ɔː l t ən /; 5 or 6 September 1766 – 27 July 1844) was an English chemist, physicist and meteorologist. [1] He introduced the atomic theory into chemistry.

  4. History of molecular theory - Wikipedia

    en.wikipedia.org/wiki/History_of_molecular_theory

    John Dalton's union of atoms combined in ratios (1808) Similar to these views, in 1803 John Dalton took the atomic weight of hydrogen, the lightest element, as unity, and determined, for example, that the ratio for nitrous anhydride was 2 to 3 which gives the formula N 2 O 3. Dalton incorrectly imagined that atoms "hooked" together to form ...

  5. Plum pudding model - Wikipedia

    en.wikipedia.org/wiki/Plum_pudding_model

    The plum pudding model was the first scientific model of the atom to describe an internal structure. It was first proposed by J. J. Thomson in 1904 following his discovery of the electron in 1897, and was rendered obsolete by Ernest Rutherford 's discovery of the atomic nucleus in 1911.

  6. Atom - Wikipedia

    en.wikipedia.org/wiki/Atom

    Various atoms and molecules from A New System of Chemical Philosophy (John Dalton 1808). In the early 1800s, John Dalton compiled experimental data gathered by him and other scientists and discovered a pattern now known as the "law of multiple proportions". He noticed that in any group of chemical compounds which all contain two particular ...

  7. Rutherford model - Wikipedia

    en.wikipedia.org/wiki/Rutherford_model

    The Rutherford model is a name for the first model of an atom with a compact nucleus. The concept arose from Ernest Rutherford discovery of the nucleus. Rutherford directed the Geiger–Marsden experiment in 1909, which showed much more alpha particle recoil than J. J. Thomson's plum pudding model of the atom could explain. Thomson's model had ...

  8. History of subatomic physics - Wikipedia

    en.wikipedia.org/wiki/History_of_subatomic_physics

    In the 19th century, John Dalton, through his work on stoichiometry, concluded that each chemical element was composed of a single, unique type of particle. Dalton and his contemporaries believed those were the fundamental particles of nature and thus named them atoms, after the Greek word atomos, meaning "indivisible" [3] or "uncut". However ...

  9. History of the periodic table - Wikipedia

    en.wikipedia.org/wiki/History_of_the_periodic_table

    Dalton's 1806 list of known elements by atomic weight. In 1808–10, British natural philosopher John Dalton published a method by which to arrive at provisional atomic weights for the elements known in his day, from stoichiometric measurements and reasonable inferences. Dalton's atomic theory was adopted by many chemists during the 1810s and ...