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  2. Discovery of chemical elements - Wikipedia

    en.wikipedia.org/wiki/Discovery_of_chemical_elements

    The two discovered a new element in a molybdenum sample that was used in a cyclotron, the first element to be discovered by synthesis. It had been predicted by Mendeleev in 1871 as eka-manganese. [171] [172] [173] In 1952, Paul W. Merrill found its spectral lines in S-type red giants. [174]

  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 28 January 2025. 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 extended ...

  4. Mendeleev's predicted elements - Wikipedia

    en.wikipedia.org/wiki/Mendeleev's_predicted_elements

    Dmitri Mendeleev published a periodic table of the chemical elements in 1869 based on properties that appeared with some regularity as he laid out the elements from lightest to heaviest. [1] When Mendeleev proposed his periodic table, he noted gaps in the table and predicted that then-unknown elements existed with properties appropriate to fill ...

  5. Unbiunium - Wikipedia

    en.wikipedia.org/wiki/Unbiunium

    In the periodic table of the elements, it is expected to be the first of the superactinides, and the third element in the eighth period. It has attracted attention because of some predictions that it may be in the island of stability. It is also likely to be the first of a new g-block of elements. Unbiunium has not yet been synthesized.

  6. Periodic table - Wikipedia

    en.wikipedia.org/wiki/Periodic_table

    The periodic table is a graphic description of the periodic law, [36] which states that the properties and atomic structures of the chemical elements are a periodic function of their atomic number. [37] Elements are placed in the periodic table according to their electron configurations, [38] the periodic recurrences of which explain the trends ...

  7. Extended periodic table - Wikipedia

    en.wikipedia.org/wiki/Extended_periodic_table

    An extended periodic table theorizes about chemical elements beyond those currently known and proven. The element with the highest atomic number known is oganesson (Z = 118), which completes the seventh period (row) in the periodic table. All elements in the eighth period and beyond thus remain purely hypothetical.

  8. Mendelevium - Wikipedia

    en.wikipedia.org/wiki/Mendelevium

    Mendelevium was discovered by bombarding einsteinium with alpha particles in 1955, the method still used to produce it today. It is named after Dmitri Mendeleev, the father of the periodic table. Using available microgram quantities of einsteinium-253, over a million mendelevium atoms may be made each hour. The chemistry of mendelevium is ...

  9. Tennessine - Wikipedia

    en.wikipedia.org/wiki/Tennessine

    Tennessine may be located in the "island of stability", a concept that explains why some superheavy elements are more stable despite an overall trend of decreasing stability for elements beyond bismuth on the periodic table. The synthesized tennessine atoms have lasted tens and hundreds of milliseconds.