Radium atomic emission

Within only two years of Soddy and Rutherford s papers on atomic transformation as the mechanism for radioactivity, writers of popular fiction did indeed make the shift from cathode rays pulling an unknown element from the moon to radium emissions and other such atomic technologies causing alchemical transmutation—and similarly fretted about the consequences to the gold-standard economy of the West. Rider Haggard s Ayesha The Return of She (1904-05) was noteworthy, as we have mentioned, because... 

A radioactive element is an element that disintegrates spontaneously with the emission of various rays and particles. Most commonly, the term denotes radioactive elements such as radium, radon (emanation), thorium, promethium, uranium, which occupy a definite place in the periodic table because of their atomic number. The term radioactive element is also applied to the various other nuclear species, (which arc produced by the disintegration of radium, uranium, etc.) including (he members of the uranium, actinium, thorium, and neptunium families of radioactive elements, which differ markedly in their stability, and are isotopes of elements from thallium (atomic number 81) to uranium (atomic number... 

In spite of all the new approaches which illuminated the outer regions of the atom, the center or nucleus of the atom continued to remain a bundle of uncertainties. Something of the composition of the nuclei of a few elements was already known. This information came from a study of the spontaneous disintegration of radium and other radioactive elements, such as thorium, polonium, uranium, and radon. These elements break down of their own accord into simpler elements. Soon after the Curies discovery of radium, Rutherford and Frederick Soddy, his student and collaborator, had found that the spontaneous breaking down of radium resulted in the emission of three types of rays and particles. Radium ejected alpha particles (ionized helium atoms), beta particles (electrons), and gamma rays (similar to X-rays). In radioactive elements, at least, it was believed that the nucleus contained electrons, protons, and electrified helium particles. 

The emission of the three alpha particles (see Example 21.4) lowers the atomic number by 6 however, radium s atomic number is only 4 units lower than uranium s. Therefore, two beta particles must also have been emitted, each event raising the atomic number by 1. 

Radioactivity The spontaneous breakdown of the nucleus of an atom through the emission of particles (alpha and beta particles) and gamma radiation. Although all atomic nuclei can theoretically disintegrate, under normal conditions only a few of the naturally occurring elements such as uranium and radium undergo any significant rate of decay. 

It was in Paris that she met her future husband and fellow researcher, Pierre Curie. Working with crude equipment in a laboratory that was primitive, even by the standards of the time, she and Pierre made a most revolutionary discovery only two years after Henri Becquerel discovered radioactivity. Radioactivity, the emission of energy from certain substances, was released from inside the atom and was independent of the molecular form of the substance. The absolute proof of this assertion came only after the Curies processed over one ton of a material (pitchblende) to isolate less than a gram of pure radium. The difficult conditions under which this feat was accomplished are perhaps best stated by Sharon Bertsch McGrayne in her book Nobel Prize Women in Science (Birch Lane Press, New York, p. 23) ... 

In the same year the Curies, together with G. Bemont, isolated another radioactive substance for which they suggested the name radium. In order to prove that polonium and radium were in fact two new elements, large amounts of pitchblende were processed, and in 1902 M. Curie announced that she had been able to isolate about 0.1 g of pure radium chloride from more than one ton of pitchblende waste. The determination of the atomic weight of radium and the measurement of its emission spectrum provided the final proof that a new element had been isolated. 

According to Rutherford and Soddy, the mechanism of radioactive decay consists in transformation of chemical elements and in their natural transmutation. This was particularly clear in the case of radium, which converted into radon after emission of alpha radiation. Somewhat later, the alpha particle was found to be a doubly ionized helium atom. The decay of radium gave rise to two new elements, namely, radon and helium ... 

Colored images of the radioactive emission of radium (Ra). The models show the nuclei of radium and the radioactive decay products—radon (Rn) and an alpha particle, which has two protons and two neutrons. Study of radioactivity helped to advance scientists knowledge about atomic structure. 

Colored images of the radioactive emission of radium (Ra). Study of radioactivity helped to advance scientists knowledge about atomic structure. 

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