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  2. 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 ...

  3. Discovery of chemical elements - Wikipedia

    en.wikipedia.org/wiki/Discovery_of_chemical_elements

    Perey discovered it as a decay product of 227 Ac. [177] Francium was the last element to be discovered in nature, rather than synthesized in the lab, although four of the "synthetic" elements that were discovered later (plutonium, neptunium, astatine, and promethium) were eventually found in trace amounts in nature as well. [178]

  4. Electron - Wikipedia

    en.wikipedia.org/wiki/Electron

    In turn, he divided the shells into a number of cells each of which contained one pair of electrons. With this model Langmuir was able to qualitatively explain the chemical properties of all elements in the periodic table, [54] which were known to largely repeat themselves according to the periodic law. [56]

  5. Periodic table - Wikipedia

    en.wikipedia.org/wiki/Periodic_table

    Periodic table of the chemical elements showing the most or more commonly named sets of elements (in periodic tables), and a traditional dividing line between metals and nonmetals. The f-block actually fits between groups 2 and 3 ; it is usually shown at the foot of the table to save horizontal space.

  6. History of atomic theory - Wikipedia

    en.wikipedia.org/wiki/History_of_atomic_theory

    The modern periodic table is based on atomic number, which is equivalent to the nuclear charge, a change had to wait for the discovery of the nucleus. [37]: 228 In addition, an entire row of the table was not shown because the noble gases had not been discovered when Mendeleev devised his table. [37]: 222

  7. Extended periodic table - Wikipedia

    en.wikipedia.org/wiki/Extended_periodic_table

    This is an accepted version of this page This is the latest accepted revision, reviewed on 19 January 2025. Periodic table of the elements with eight or more periods Extended periodic table Hydrogen Helium Lithium Beryllium Boron Carbon Nitrogen Oxygen Fluorine Neon Sodium Magnesium Aluminium Silicon Phosphorus Sulfur Chlorine Argon Potassium Calcium Scandium Titanium Vanadium Chromium ...

  8. Berkelium - Wikipedia

    en.wikipedia.org/wiki/Berkelium

    This was the culmination of the Russia–US collaboration on the synthesis of the heaviest elements on the periodic table. Berkelium is a soft, silvery-white, radioactive metal. The berkelium-249 isotope emits low-energy electrons and thus is relatively safe to handle.

  9. 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.