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  2. Periodic table - Wikipedia

    en.wikipedia.org/wiki/Periodic_table

    The first periodic table to become generally accepted was that of the Russian chemist Dmitri Mendeleev in 1869; he formulated the periodic law as a dependence of chemical properties on atomic mass. As not all elements were then known, there were gaps in his periodic table, and Mendeleev successfully used the periodic law to predict some ...

  3. History of the periodic table - Wikipedia

    en.wikipedia.org/wiki/History_of_the_periodic_table

    This is an accepted version of this page This is the latest accepted revision, reviewed on 17 November 2024. Development of the table of chemical elements The American chemist Glenn T. Seaborg —after whom the element seaborgium is named—standing in front of a periodic table, May 19, 1950 Part of a series on the Periodic table Periodic table forms 18-column 32-column Alternative and ...

  4. John Newlands (chemist) - Wikipedia

    en.wikipedia.org/wiki/John_Newlands_(chemist)

    After Dmitri Mendeleev and Lothar Meyer received the Davy Medal from the Royal Society for their later 'discovery' of the periodic table in 1882, Newlands fought for recognition of his earlier work and eventually received the Davy Medal in 1887. On the Discovery of the Periodic Law and on Relations among the Atomic Weights (1884)

  5. Octet rule - Wikipedia

    en.wikipedia.org/wiki/Octet_rule

    The bonding in carbon dioxide (CO 2): all atoms are surrounded by 8 electrons, fulfilling the octet rule.. The octet rule is a chemical rule of thumb that reflects the theory that main-group elements tend to bond in such a way that each atom has eight electrons in its valence shell, giving it the same electronic configuration as a noble gas.

  6. Types of periodic tables - Wikipedia

    en.wikipedia.org/wiki/Types_of_periodic_tables

    Theodor Benfey's arrangement is an example of a continuous (spiral) table. First published in 1964, it explicitly showed the location of lanthanides and actinides.The elements form a two-dimensional spiral, starting from hydrogen, and folding their way around two peninsulas, the transition metals, and lanthanides and actinides.

  7. Moseley's law - Wikipedia

    en.wikipedia.org/wiki/Moseley's_law

    Moseley's law is an empirical law concerning the characteristic X-rays emitted by atoms. The law has been discovered and published by the English physicist Henry Moseley in 1913–1914. [ 1 ] [ 2 ] Until Moseley's work, "atomic number" was merely an element's place in the periodic table and was not known to be associated with any measurable ...

  8. Periodic trends - Wikipedia

    en.wikipedia.org/wiki/Periodic_trends

    The periodic trends in properties of elements. In chemistry, periodic trends are specific patterns present in the periodic table that illustrate different aspects of certain elements when grouped by period and/or group. They were discovered by the Russian chemist Dmitri Mendeleev in 1863.

  9. Scientific law - Wikipedia

    en.wikipedia.org/wiki/Scientific_law

    Scientific laws or laws of science are statements, based on repeated experiments or observations, that describe or predict a range of natural phenomena. [1] The term law has diverse usage in many cases (approximate, accurate, broad, or narrow) across all fields of natural science (physics, chemistry, astronomy, geoscience, biology).