Elements in the history of the Periodic Table.
Discovery of the Periodic Table was rendered possible only after four decisive prerequisites had been achieved. These were (i) the abandonment of the metaphysical and occult notions of elements that typified the alchemical era; (ii) the adoption of a modern and workable definition of an element; (iii) the development of analytical chemical techniques for the isolation of the elements and determination of their properties; and (iv) the devising of a means of associating each element with a characteristic natural number. The Periodic Table made its appearance on cue almost as soon as these preconditions had been fulfilled.
Heaviest Element Has Unusual Shell Structure Calculations of the structure in oganesson — the element with the highest atomic number — reveal a uniform , gas-like distribution of its electrons and nucleons . by
T he periodic table continues to evolve, as it has since the publication of the first widely recognized periodic table by Dmitri Mendeleev in 1869. There have been over 700 versions of the table of elements to date [1], with elements regularly being added, filling empty blocks of the table. An example is the late 19th century addition of a new column (group) of elements, the noble gases, by William Ramsay, who received the 1904 Nobel Prize in Chemistry for his discovery [2]. The most recent entry to this column is oganesson (Og), which is the element with the highest known atomic number (Z = 118) [3]. This intriguing new element, which was first synthesized in 2002, completes the seventh row (7p block) of the periodic table and is the first superheavy (Z > 103) noble gas element.
Bone changes in tuberous sclerosis mimicking metastases.
Sclerotic and lytic bone changes of tuberous sclerosis (TS) can mimic bone metastases. We report a case of bone metastases from bronchogenic carcinoma in a patient with TS bone changes. Bone scintigraphy and magnetic resonance imaging are useful in distinguishing the TS bone lesions from bone metastases.