Professor Dimitri Mendeleev published the first Periodic Table of the Atomic Elements in 1869 based on properties which 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 as of yet unknown elements existed with properties appropriate to fill those gaps. Portrait of Dimitri Mendeleyev by Ilya Repin Dimitri Mendeleev (Russian: , Dmitriy Ivanovich Mendeleyev  ) (8 February 1834 [O.S. 27 January] in Tobolsk – 2 February 1907 [O.S. 20 January] in Saint Petersburg), was a Russian chemist. ... The periodic table of the chemical elements is a tabular method of displaying the chemical elements, first devised in 1869 by the Russian chemist Dmitri Mendeleev. ...

Later predictions of elements Coronium and Ether

In 1902, having accepted the evidence for elements Helium and Argon, Mendeleev placed these Noble Gases in Group 0 in his arrangement of the elements.^[2] As Mendeleev was doubtful of atomic theory to explain the Law of definite proportions, he had no a priori reason to believe Hydrogen was the lightest of elements, and suggested that a hypothetical lighter member of these chemically inert Group 0 elements could have gone undetected and be responsible for radioactivity. High resolution spectrum of the Sun showing thousands of elemental absorption lines (fraunhofer lines). ... The luminiferous aether: it was hypothesised that the Earth moves through a medium of aether that carries light In the late 19th century luminiferous aether (light-bearing aether) was the term used to describe a medium for the propagation of light. ... General Name, Symbol, Number helium, He, 2 Chemical series noble gases Group, Period, Block 18, 1, s Appearance colorless Atomic mass 4. ... General Name, Symbol, Number argon, Ar, 18 Chemical series noble gases Group, Period, Block 18, 3, p Appearance colorless Atomic mass 39. ... For the musical band, see Noble Gas (band) The noble gases are the chemical elements in group 18 (old-style Group 0) of the periodic table. ... Various atoms and molecules as depicted in John Daltons A New System of Chemical Philosophy (1808). ... One of the fundamental observations of modern chemistry made by Joseph Louis Proust, the law of definite proportions states that, in a pure compound, the elements combine in definite proportions to each other by mass. ... General Name, Symbol, Number hydrogen, H, 1 Chemical series nonmetals Group, Period, Block 1, 1, s Appearance colorless Atomic mass 1. ... Radioactivity may mean: Look up radioactivity in Wiktionary, the free dictionary. ...

The heavier of the hypothetical proto-Helium elements Mendeleev identified with Coronium, an unexplained spectral line in the Sun's corona. A faulty calibration gave a wavelength of 531.68 nm, which was eventually corrected to 530.3 nm, which Grotrian and Edlen identified as originating from Fe XIV in 1939.^[3] In astronomy, a corona is the luminous plasma atmosphere of the Sun or other celestial body, extending millions of kilometres into space, most easily seen during a total solar eclipse, but also observable in a coronagraph. ...

The lightest of the Zero Group gases, the first in the Periodic Table, was assigned a theoretical atomic mass between 5.3 x 10^-11 and 9.6 x 10^-7. The kinetic velocity of this gas was calculated by Mendeleev to be 2,500,000 meters per second. Nearly massless, these gases were assumed by Mendeleev to permeate all matter, rarely interacting chemically. The high mobility and very small mass of the trans-hydrogen gases would result in the situation, that they could be rarefied, yet appear to be very dense. ^[4] Mendeleev was so confident that these atomic elements would be discovered, that he included them in later publications of the periodic chart, although there was no physical evidence for their existence available at the time. ^{[citation needed]}

Mendeleev later published a theoretical expression of the aether, which satisfied^{[citation needed]} many of the contradictions which existed in physics at that time, in a small booklet entitled, A Chemical Conception of the Ether, in 1904. His 1904 publication again contained two atomic elements smaller and lighter than hydrogen. He treated the “aether gas” as an interstellar atmosphere composed of at least two lighter-than-hydrogen elements. He stated that these gases originated due to violent bombardments internal to stars, the sun being the most prolific source of such gases. According to Mendeleev's booklet, the interstellar atmosphere was probably composed of several additional elemental species.

In 1905, Albert Einstein demonstrated that Brownian motion resulted as the natural consequence of the atomic theory. Later, atomic number was determined to be more natural than atomic weight in classifying the elements, and while Mendeleev genius persists in the table's arrangement, Hydrogen, with atomic number 1, was confirmed as the unique lightest element. 1905 (MCMV) was a common year starting on Sunday (see link for calendar). ... Einstein redirects here. ... Three different views of Brownian motion, with 32 steps, 256 steps, and 2048 steps denoted by progressively lighter colors. ... In chemistry and physics, the atomic number (Z) is the number of protons found in the nucleus of an atom. ... ...

Original Predictions from 1869

To give provisional names to his predicted elements, Mendeleev used the prefixes eka-, dvi-, and tri-, from the Sanskrit words for one, two, and three, depending upon whether the predicted element was one, two, or three places away from the known element in his table with similar chemical properties. The Sanskrit language ( , ) is a classical language of India, a liturgical language of Hinduism, Buddhism, and Jainism, and one of the 22 official languages of India. ...

The four predicted elements lighter than the rare earth elements, ekaboron (Eb), ekaaluminium (symbol El), ekamanganese (Em), and ekasilicon (Es), proved to be good predictors of the properties of scandium, gallium, technetium and germanium respectively, which each fill the spot in the periodic table assigned by Mendeleev. Initial versions of the periodic table did not give the rare earth elements the treatment now given them, helping to explain both why Mendeleev’s predictions for heavier unknown elements did not fare as well as those for the lightest predictions and why they are not as well known or documented. Rare earth ore Rare earth elements and rare earth metals are trivial names sometimes applied to a collection of 17 chemical elements in the periodic table, namely scandium, yttrium, and the lanthanides. ... General Name, Symbol, Number scandium, Sc, 21 Chemical series transition metals Group, Period, Block 3, 4, d Appearance silvery white Atomic mass 44. ... General Name, Symbol, Number gallium, Ga, 31 Chemical series poor metals Group, Period, Block 13, 4, p Appearance silvery white   Atomic mass 69. ... General Name, Symbol, Number technetium, Tc, 43 Chemical series transition metals Group, Period, Block 7, 5, d Appearance silvery gray metal Atomic mass [98](0) g/mol Electron configuration [Kr] 4d5 5s2 Electrons per shell 2, 8, 18, 13, 2 Physical properties Phase solid Density (near r. ... General Name, Symbol, Number germanium, Ge, 32 Chemical series metalloids Group, Period, Block 14, 4, p Appearance grayish white Atomic mass 72. ...

Nowadays, the prefix eka- (and, more rarely, dvi-) is sometimes used in discussions about undiscovered (and highly speculative after 138) elements, such as untriennium, a.k.a. eka-actinium or dvi-lanthanum. General Name, Symbol, Number untriennium, Ute, 139 Chemical series Group, Period, Block 3, 8, f Appearance  ? Image:.jpg Atomic mass  ? g/mol Electron configuration Electrons per shell Physical properties Phase presumably solid Miscellaneous Notable isotopes References Untriennium (eka-actinium/dvi-lanthanum) is an unsynthesized chemical element with atomic number 139...

Ekaboron and Scandium

Scandium was isolated as the oxide in spring, 1879, by Lars Fredrick Nilson; Per Teodor Cleve recognized the correspondence and notified Mendeleev late in that year. Mendeleev had predicted an atomic mass of 44 for ekaboron in 1871 while scandium has an atomic mass of 44.955910. General Name, Symbol, Number scandium, Sc, 21 Chemical series transition metals Group, Period, Block 3, 4, d Appearance silvery white Atomic mass 44. ... 1879 (MDCCCLXXIX) was a common year starting on Wednesday (see link for calendar). ... Per Teodor Cleve (Stockholm February 10, 1840 – Uppsala June 18, 1905) was a Swedish chemist and geologist. ...

Ekaaluminium and Gallium

In 1871 Mendeleev predicted the existence of yet undiscovered element he named eka-aluminum (because of its proximity to aluminum in the periodic table). The table below compares the qualities of the element predicted by Mendeleev with actual characteristics of Gallium (discovered in 1875) General Name, Symbol, Number gallium, Ga, 31 Chemical series poor metals Group, Period, Block 13, 4, p Appearance silvery white   Atomic mass 69. ...

Ekamanganese and Technetium

Technetium was isolated by Carlo Perrier and Emilio Segrè in 1937, well after Mendeleev’s lifetime, from samples of molybdenum that had been bombarded with deuterium nuclei in a cyclotron by Ernest Lawrence. Mendeleev had predicted an atomic mass of 100 for ekamanganese in 1871 and the most stable isotope of technetium is ⁹⁸Tc. ^[5] General Name, Symbol, Number technetium, Tc, 43 Chemical series transition metals Group, Period, Block 7, 5, d Appearance silvery gray metal Atomic mass [98](0) g/mol Electron configuration [Kr] 4d5 5s2 Electrons per shell 2, 8, 18, 13, 2 Physical properties Phase solid Density (near r. ... Portrait of Dr. Emilio Segre Emilio Gino Segrè (February 1, 1905 - April 22, 1989) was an Italian American physicist who, with Owen Chamberlain, won the 1959 Nobel Prize in Physics for their discovery of the antiproton. ... 1937 (MCMXXXVII) was a common year starting on Friday (link will take you to calendar). ... General Name, Symbol, Number molybdenum, Mo, 42 Chemical series transition metals Group, Period, Block 6, 5, d Appearance gray metallic Atomic mass 95. ... Deuterium, also called heavy hydrogen, is a stable isotope of hydrogen with a natural abundance in the oceans of planet Earth of approximately one atom in 6500 of hydrogen (~154 PPM). ... A pair of Dee electrodes with loops of coolant pipes on their surface at the Lawrence Hall of Science. ... Ernest O. Lawrence Ernest Orlando Lawrence (August 8, 1901 – August 27, 1958) was an American physicist and Nobel Laureate best known for his invention, utilization, and improvement of the cyclotron beginning in 1929, and his later work in uranium-isotope separation in the Manhattan Project. ...

Ekasilicon and Germanium

Germanium was isolated in 1882, and provided the best confirmation of the theory up to that time, due to its contrasting more clearly with its neighboring elements than the two previously confirmed predictions of Mendeleev do with theirs. General Name, Symbol, Number germanium, Ge, 32 Chemical series metalloids Group, Period, Block 14, 4, p Appearance grayish white Atomic mass 72. ... 1882 (MDCCCLXXXII) was a common year starting on Sunday (see link for calendar) of the Gregorian calendar or a common year starting on Tuesday of the 12-day slower Julian calendar. ...

The term refractory can refer to multiple things: A refractory clergyman is one who refused to swear an oath to the French Revolution-era French state under the Civil Constitution of the Clergy. ...

References

1. ^ Kaji, Masanori (2002). "D.I.Mendeleev's concept of chemical elements and The Principles of Chemistry". Bulletin for the History of Chemistry 27 (1): 4-16.
2. ^ Mendeleev, D. (1902-1903). Osnovy Khimii [The Principles of Chemistry], 7th edition (in Russian).
3. ^ Swings, P. (July 1943). "Edlén's Identification of the Coronal Lines with Forbidden Lines of Fe X, XI, XIII, XIV, XV; Ni XII, XIII, XV, XVI; Ca XII, XIII, XV; a X, XIV". Astrophysical Journal 98: 116-124. DOI:10.1086/144550.and
   http://laserstars.org/spectra/Coronium.html
4. ^ Mendeleev, D. (1903). Popytka khimicheskogo ponimaniia mirovogo efira (in Russian).
   An English translation appeared as
   Mendeléeff, D. (1904). G. Kamensky (translator): An Attempt Towards A Chemical Conception Of The Ether. New York: Longmans, Green & Co..
   See also
   Bensaude-Vincent, Bernadette (1982). "L’éther, élément chimique: un essai malheureux de Mendéleev en 1904". British Journal for the History of Science 15: 183-188.
5. ^ This is atomic mass number of 98 which is distinct from an atomic mass in that it is a count of nucleons in the nucleus of one isotope and is not an actual weight of an average sample (with a natural collection of isotopes) relative to ¹²C. The ⁹⁸Tc isotope has a mass of 97.907214. For elements which are not stable enough to persist from the creation of the Earth, the convention is to report the atomic mass number of the most stable isotope in place of the naturally occurring atomic mass average. http://chemlab.pc.maricopa.edu/PERIODIC/Tc.html