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Cannizzaro, S.

doi:10.1007/bf02735624

Cited by 16 publications

(26 citation statements)

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“…The CAWIA report in 1961 [22] recommended the atomic weight A r (P) = 30.9738, based on atomic mass data from Everling et al [23], and quoted experimental evidence from the literature concerning upper limits for the hypothetical presence of 28 P, 29 P, 30 P, 32 P, 33 P, and 34 P. This evidence, however, does not rule out an effect on A r (P) in the seventh significant figure. The revision of the atomic mass data by Wapstra and Gove [48] led to a refinement of A r (P) to 30.973 76(1) in the 1971 CAWIA report [5].…”

confidence: 88%

“…The pure metal was first isolated by the German chemist Friedrich Wöhler in 1827. The CAWIA report in 1961 [22] proposed the atomic weight of Al to be A r (Al) = 26.9815, based on atomic mass data by Everling et al [23], and experimental evidence from the literature concerning upper limits for the hypothetical presence of 25 Al, 26 Al, 28 Al, 29 Al, and 30 Al [127]. This evidence shows that these isotopes could at most affect A r (Al) by one digit in the seventh significant figure.…”

confidence: 99%

“…The Italian chemist Stanislao Cannizzaro presented his "Sketch of a Course in Theoretical Chemistry" [29], in which he called attention to the value of Avogadro's distinction between atoms and molecules as an organizing device for the interpretation of chemical phenomena. The interchange of the terms "atoms" and "molecules" had led to confusion and to instances of two different atomic weights being assigned to the same element.…”

Section: Historymentioning

confidence: 99%

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Atomic weights of the elements. Review 2000 (IUPAC Technical Report)

Laeter¹,

Böhlke²,

Bièvre³

et al. 2003

Pure and Applied Chemistry

927

554

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Republication or reproduction of this report or its storage and/or dissemination by electronic means is permitted without the need for formal IUPAC permission on condition that an acknowledgmentAbstract: A consistent set of internationally accepted atomic weights has long been an essential aim of the scientific community because of the relevance of these values to science and technology, as well as to trade and commerce subject to ethical, legal, and international standards. The standard atomic weights of the elements are regularly evaluated, recommended, and published in updated tables by the Commission on Atomic Weights and Isotopic Abundances (CAWIA) of the International Union of Pure and Applied Chemistry (IUPAC). These values are invariably associated with carefully evaluated uncertainties. Atomic weights were originally determined by mass ratio measurements coupled with an understanding of chemical stoichiometry, but are now based almost exclusively on knowledge of the isotopic composition (derived from isotope-abundance ratio measurements) and the atomic masses of the isotopes of the elements. Atomic weights and atomic masses are now scaled to a numerical value of exactly 12 for the mass of the carbon isotope of mass number 12. Technological advances in mass spectrometry and nuclear-reaction energies have enabled atomic masses to be determined with a relative uncertainty of better than 1 × 10 -7 . Isotope abundances for an increasing number of elements can be measured to better than 1 × 10 -3 . The excellent precision of such measurements led to the discovery that many elements, in different specimens, display significant variations in their isotope-abundance ratios, caused by a variety of natural and industrial physicochemical processes. While such variations increasingly place a constraint on the uncertainties with which some standard atomic weights can be stated, they provide numerous opportunities for investigating a range of important phenomena in physical, chemical, cosmological, biological, and industrial processes. This review reflects the current and increasing interest of science in the measured differences between source-specific and even sample-specific atomic weights. These relative comparisons can often be made with a smaller uncertainty than is achieved in the best calibrated "absolute" (= SI-traceable) atomic-weight determinations. Accurate determinations of the atomic weights of certain elements also influence the values of fundamental constants such as the Avogadro, Faraday, and universal gas constants. This review is in two parts: the first summarizes the development of the science of atomic-weight determinations during the 20 th century; the second summarizes the changes and variations that have been recognized in the values and uncertainties of atomic weights, on an element-by-element basis, in the latter part of the 20 th century.J. R. de LAETER et al.

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confidence: 88%

confidence: 99%

Section: Historymentioning

confidence: 99%

See 1 more Smart Citation

Atomic weights of the elements. Review 2000 (IUPAC Technical Report)

Laeter¹,

Böhlke²,

Bièvre³

et al. 2003

Pure and Applied Chemistry

927

554

View full text Add to dashboard Cite

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“…However, more "theoryladen" [18] concepts had to be added. [3q, 5] Namely, in 1860 [19] the atomic weight A, based on physicochemical laws (namely for gases, specific heats, and colligative effects) and in 1913 [20] the nuclear charge number Z. The atomic cores enabled linear ordering of the elements, while the properties of the valence shells suggest a network according to chemical similarity.…”

Section: One System-many Tablesmentioning

confidence: 99%

Icon of Chemistry: The Periodic System of Chemical Elements in the New Century

Wang

Schwarz

2009

Angew Chem Int Ed

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A closer look: A deeper theoretical understanding of the multifaceted periodic system of elements (PSE) has been achieved in recent years. The large energy gaps above the noble gas shells 1s(2) and np(6) (n=2-6) impress periodicity onto the whole PSE, which is complete with Period 7. The electron configurations of unbound atoms are chemically misleading. The common n+l rule is an example of the "invention of facts" even in the hard sciences.

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“…[31] Looking at phosphoric acid, he showed that this was not surprising: for the same reason we accept the existence of three phosphoric acids, combined with different bases, so we can also assert that there are two different modifications of the same mercuric or ramic (cupric) radical.…”

Section: The Schoolmentioning

confidence: 90%

Stanislao Cannizzaro and the Development of Chemistry in Palermo from 1862 to 1871

Zingales

2009

Chemistry A European J

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Stanislao Cannizzaro worked at Palermo University for about ten years. There he managed to establish a modern and well-equipped chemical laboratory. His international fame attracted co-workers even from abroad: Naquet, Lieben, and Körner came to Palermo to work with him. This greatly improved the quality of teaching and of research in Palermo, which became a worldwide acknowledged center of chemical culture. In Palermo, atomic-molecular theory was extensively taught and research was carried out on chemical atomicity (valence) and spatial structures of both aliphatic and aromatic organic molecules: Körner found the relative positions of substituent groups on the benzene ring, Paternò proved the equivalence of the four positions around each carbon atom. Thanks to Cannizzaro's and Paternò's efforts, a new journal, Gazzetta Chimica Italiana, was printed in Palermo. The journal collected original papers from Italian chemists, and summaries or translations of foreign ones. When Cannizzaro moved to Rome in 1872, Emanuele Paternò, the youngest of his pupils, took his place. Eventually, Paternò also moved to Rome, and the leading role of Palermo in Italian chemistry faded.

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Osservazioni sulla nota precedente

Cited by 16 publications

References 0 publications

Atomic weights of the elements. Review 2000 (IUPAC Technical Report)

Atomic weights of the elements. Review 2000 (IUPAC Technical Report)

Icon of Chemistry: The Periodic System of Chemical Elements in the New Century

Stanislao Cannizzaro and the Development of Chemistry in Palermo from 1862 to 1871

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