The Nucleus and the Periodic Table: Radioactivity, Atomic Number, and Isotopy

2019 ◽  
Author(s):  
Eric Scerri
Keyword(s):  
Nineteenth Century ◽  
Twentieth Century ◽  
Nuclear Structure ◽  
Atomic Number ◽  
Alpha Particle ◽  
Periodic Table ◽  
Radioactive Decay ◽  
X Rays ◽  
Harsh Criticism ◽  
Influence Attempts

Theories of the atom were reintroduced into science by John Dalton and were taken up and debated by chemists in the nineteenth century. As noted in preceding chapters, atomic weights and equivalent weights were determined and began to influence attempts to classify the elements. Many physicists were at first reluctant to accept the notion of atoms, with the tragic exception of Ludwig Boltzmann, who came under such harsh criticism for his support of atomism that he eventually took his own life. But around the turn of the twentieth century, the tide began to turn, and physicists not only adopted the atom but transformed the whole of science by performing numerous experiments aimed at probing its structure. Their work had a profound influence on chemistry and, more specifically for our interests here, the explanation and presentation of the periodic table. Beginning with J.J. Thomson’s discovery of the electron in 1897, developments came quickly. In 1911, Ernest Rutherford proposed the nuclear structure of the atom, and by 1920 he had named the proton and the neutron. All of this work was made possible by the discovery of X-rays in 1895, which allowed physicists to probe the atom, and by the discovery of radioactivity in 1896. The phenomenon of radioactivity destroyed the ancient concept of the immutability of the atom once and for all and demonstrated that one element could be transformed into another, thus in a sense achieving the goal that the alchemists had sought in vain. The discovery of radioactivity led to the eventual realization that the atom, which took its name from the idea that it was indivisible, could in fact be subdivided into more basic particles: the proton, neutron, and electron. Rutherford was the first to try to “split the atom,” something he achieved by using one of the newly discovered products of radioactive decay, the alpha particle.

6. Physics invades the periodic table

2019 ◽  
pp. 73-84
Author(s):  
Eric R. Scerri
Keyword(s):  
Nuclear Structure ◽  
Atomic Number ◽  
Periodic Table ◽  
Atomic Weight ◽  
Ernest Rutherford ◽  
Frederick Soddy ◽  
The Impact

‘Physics invades the periodic table’ assesses the impact of key discoveries in physics on the understanding of the periodic table. Ernest Rutherford provided evidence for the nuclear structure of atoms, and also determined that the charge of an atom is equal to half its atomic weight. Anton van den Broek linked this principle to the number of protons in a nucleus, thus devising the notion of atomic number. Henry Moseley quantified this principle, and used it to show exactly how many elements would fill the gaps in the periodic table. Radioactive experiments created new forms of elements with different weights but the same charge, which Frederick Soddy identified as isotopes.

The Invasion of the Periodic Table by Physics

2013 ◽  
Author(s):  
Eric Scerri
Keyword(s):  
Twentieth Century ◽  
Brownian Motion ◽  
Periodic System ◽  
Periodic Table ◽  
X Rays ◽  
Cavendish Laboratory ◽  
Experimental Support ◽  
Experimental Physicist ◽  
Scientific Life

Although John Dalton had reintroduced the notion of atoms to science, many debates followed among chemists, most of whom refused to accept that atoms existed literally. One of these skeptical chemists was Mendeleev, but as we saw in the previous chapter this does not seem to have prevented him from publishing the most successful periodic system of all those proposed at the time. Following the work of physicists like Einstein and Perrin, the atom’s reality became more and more firmly established starting at the turn of the twentieth century. Einstein’s 1905 paper on Brownian motion, using statistical methods, provided conclusive theoretical justification for the existence of atoms but lacked experimental support. The latter was soon provided by the French experimental physicist Jean Perrin. This work led in turn to many lines of research aimed at exploring the structure of the atom, and many developments that were to have a big influence on attempts to understand the periodic system theoretically. In this chapter we consider some of this atomic research as well as several other key discoveries in twentieth-century physics that contributed to what might be called the invasion of the periodic table by physics. The discovery of the electron, the first hint that the atom had a substructure, came in 1897 at the hands of the legendary J. J. Thomson, working at the Cavendish laboratory in Cambridge. A little earlier, in 1895, Wilhelm Conrad Röntgen had discovered X-rays in Würzburg, Germany. These new rays would soon be put to very good use by Henry Moseley, a young physicist working first in Manchester and, for the remainder of his short scientific life, in Oxford. Just a year after Röntgen had described his X-rays, Henri Becquerel in Paris discovered the enormously important phenomenon of radioactivity, whereby certain atoms break up spontaneously while emitting a number of different, new kinds of rays. The term “radioactivity” was actually coined by the Polish-born Marie Slodowska (later Curie).

Contribution of x-ray total reflection to the background intensity in EPMA

1990 ◽  
Vol 48 (2) ◽  
pp. 202-203
Author(s):  
Werner P. Rehbach ◽  
Peter Karduck
Keyword(s):  
Atomic Number ◽  
Target Material ◽  
Total Reflection ◽  
Background Intensity ◽  
X Rays ◽  
Characteristic Radiation ◽  
X Ray

In the EPMA of soft x rays anomalies in the background are found for several elements. In the literature extremely high backgrounds in the region of the OKα line are reported for C, Al, Si, Mo, and Zr. We found the same effect also for Boron (Fig. 1). For small glancing angles θ, the background measured using a LdSte crystal is significantly higher for B compared with BN and C, although the latter are of higher atomic number. It would be expected, that , characteristic radiation missing, the background IB (bremsstrahlung) is proportional Zn by variation of the atomic number of the target material. According to Kramers n has the value of unity, whereas Rao-Sahib and Wittry proposed values between 1.12 and 1.38 , depending on Z, E and Eo. In all cases IB should increase with increasing atomic number Z. The measured values are in discrepancy with the expected ones.

Songs of the spirit from Dufftown

2019 ◽  
Vol 70 (1) ◽  
pp. 36-54
Author(s):  
Shelagh Noden
Keyword(s):  
Nineteenth Century ◽  
Twentieth Century ◽  
Church Music ◽  
Early Years ◽  
Liturgical Music

Following the Scottish Catholic Relief Act of 1793, Scottish Catholics were at last free to break the silence imposed by the harsh penal laws, and attempt to reintroduce singing into their worship. At first opposed by Bishop George Hay, the enthusiasm for liturgical music took hold in the early years of the nineteenth century, but the fledgling choirs were hampered both by a lack of any tradition upon which to draw, and by the absence of suitable resources. To the rescue came the priest-musician, George Gordon, a graduate of the Royal Scots College in Valladolid. After his ordination and return to Scotland he worked tirelessly in forming choirs, training organists and advising on all aspects of church music. His crowning achievement was the production, at his own expense, of a two-volume collection of church music for the use of small choirs, which remained in use well into the twentieth century.

Scottish Missionaries, ‘Protestant Hinduism’ and the Scottish Sense of Empire in Nineteenth- and Early Twentieth-century India

2007 ◽  
Vol 86 (2) ◽  
pp. 278-313 ◽  
Author(s):  
Philip Constable
Keyword(s):  
Nineteenth Century ◽  
Twentieth Century ◽  
Late Nineteenth Century ◽  
Western India ◽  
Early Nineteenth Century ◽  
Church Of Scotland ◽  
Free Church ◽  
Intellectual Engagement ◽  
Late Nineteenth ◽  
The Church

This article examines the Scottish missionary contribution to a Scottish sense of empire in India in the nineteenth and early twentieth centuries. Initially, the article reviews general historiographical interpretations which have in recent years been developed to explain the Scottish relationship with British imperial development in India. Subsequently the article analyses in detail the religious contributions of Scottish Presbyterian missionaries of the Church of Scotland and the Free Church Missions to a Scottish sense of empire with a focus on their interaction with Hindu socioreligious thought in nineteenth-century western India. Previous missionary historiography has tended to focus substantially on the emergence of Scottish evangelical missionary activity in India in the early nineteenth century and most notably on Alexander Duff (1806–78). Relatively little has been written on Scottish Presbyterian missions in India in the later nineteenth century, and even less on the significance of their missionary thought to a Scottish sense of Indian empire. Through an analysis of Scottish Presbyterian missionary critiques in both vernacular Marathi and English, this article outlines the orientalist engagement of Scottish Presbyterian missionary thought with late nineteenth-century popular Hinduism. In conclusion this article demonstrates how this intellectual engagement contributed to and helped define a Scottish missionary sense of empire in India.

A Well-Ordered Thing

2018 ◽  
Author(s):  
Michael D. Gordin
Keyword(s):  
Nineteenth Century ◽  
History Of Science ◽  
Periodic Table ◽  
The Arctic ◽  
Classic Work ◽  
Hot Air ◽  
History Of ◽  
First Time

Dmitrii Mendeleev (1834–1907) is a name we recognize, but perhaps only as the creator of the periodic table of elements. Generally, little else has been known about him. This book is an authoritative biography of Mendeleev that draws a multifaceted portrait of his life for the first time. As the book reveals, Mendeleev was not only a luminary in the history of science, he was also an astonishingly wide-ranging political and cultural figure. From his attack on Spiritualism to his failed voyage to the Arctic and his near-mythical hot-air balloon trip, this is the story of an extraordinary maverick. The ideals that shaped his work outside science also led Mendeleev to order the elements and, eventually, to engineer one of the most fascinating scientific developments of the nineteenth century. This book is a classic work that tells the story of one of the world's most important minds.

Historical Fragments’ Mobile Echo

Transfers ◽  
2017 ◽  
Vol 7 (2) ◽  
pp. 115-119 ◽  
Author(s):  
Susan E. Bell ◽  
Kathy Davis
Keyword(s):  
Nineteenth Century ◽  
Twentieth Century ◽  
Eighteenth Century ◽  
Cultural Revolution ◽  
Ming Dynasty ◽  
Third Century ◽  
Refugee Crisis ◽  
The Third ◽  
Opium War ◽  
The Subject

Translocation – Transformation is an ambitious contribution to the subject of mobility. Materially, it interlinks seemingly disparate objects into a surprisingly unified exhibition on mobile histories and heritages: twelve bronze zodiac heads, silk and bamboo creatures, worn life vests, pressed Pu-erh tea, thousands of broken antique teapot spouts, and an ancestral wooden temple from the Ming dynasty (1368–1644) used by a tea-trading family. Historically and politically, the exhibition engages Chinese stories from the third century BCE, empires in eighteenth-century Austria and China, the Second Opium War in the nineteenth century, the Chinese Cultural Revolution of the mid-twentieth century, and today’s global refugee crisis.

Veiling Esther, Unveiling Her Story

2018 ◽  
Author(s):  
Adam J. Silverstein
Keyword(s):  
Nineteenth Century ◽  
Twentieth Century ◽  
Case Studies ◽  
Muslim World ◽  
Historical Narratives ◽  
Modern Times ◽  
Religious Background ◽  
Literary Context ◽  
Shed Light ◽  
Selection Of

This book examines the ways in which the biblical book of Esther was read, understood, and used in Muslim lands, from ancient to modern times. It zeroes-in on a selection of case studies, covering works from various periods and regions of the Muslim world, including the Qur’an, premodern historical chronicles and literary works, the writings of a nineteenth-century Shia feminist, a twentieth-century Iranian dictionary, and others. These case studies demonstrate that Muslim sources contain valuable materials on Esther, which shed light both on the Esther story itself and on the Muslim peoples and cultures that received it. The book argues that Muslim sources preserve important, pre-Islamic materials on Esther that have not survived elsewhere, some of which offer answers to ancient questions about Esther, such as the meaning of Haman’s epithet in the Greek versions of the story, the reason why Mordecai refused to prostrate himself before Haman, and the literary context of the “plot of the eunuchs” to kill the Persian king. Furthermore, throughout the book we will see how each author’s cultural and religious background influenced his or her understanding and retelling of the Esther story: In particular, it will be shown that Persian Muslims (and Jews) were often forced to reconcile or choose between the conflicting historical narratives provided by their religious and cultural heritages respectively.

Nuclear Electrons and Nuclear Structure

2018 ◽  
Author(s):  
Roger H. Stuewer
Keyword(s):  
Nuclear Structure ◽  
Beta Decay ◽  
Gamma Rays ◽  
Alpha Particle ◽  
Continuous Distribution ◽  
Alpha Particles ◽  
Light Nuclei ◽  
Coincidence Method ◽  
Wolfgang Pauli ◽  
Beta Particles

Serious contradictions to the existence of electrons in nuclei impinged in one way or another on the theory of beta decay and became acute when Charles Ellis and William Wooster proved, in an experimental tour de force in 1927, that beta particles are emitted from a radioactive nucleus with a continuous distribution of energies. Bohr concluded that energy is not conserved in the nucleus, an idea that Wolfgang Pauli vigorously opposed. Another puzzle arose in alpha-particle experiments. Walther Bothe and his co-workers used his coincidence method in 1928–30 and concluded that energetic gamma rays are produced when polonium alpha particles bombard beryllium and other light nuclei. That stimulated Frédéric Joliot and Irène Curie to carry out related experiments. These experimental results were thoroughly discussed at a conference that Enrico Fermi organized in Rome in October 1931, whose proceedings included the first publication of Pauli’s neutrino hypothesis.

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