The History of Nuclear Chemistry The main

The History of Nuclear Chemistry

The main experimental precondition for divisibility of the atom steel electric current study conducted by physicists over the XIX century. In 1874, Irish physicist George Johnstone Stoney (18261911) expressed the idea that electricity consists of elementary charges, associated with atoms, and calculated the value of the elementary charge; in 1891 Stoney suggested to him the term electron. studies of electrical discharges in rarefied gases and vacuum, which began in 1859, German Julius Plücker (1801 -1868), led to the fact that Johann Wilhelm Hittorf (1824 -1914) and William Crookes discovered in the 1869 -1875 biennium. invisible cathode rays, propagating in vacuo from the cathode to the anode.

In 1895, French physicist Jean Baptiste Perrin (1870 -1942) found deviation of the electric field of the cathode rays, thus proving that they represent a flow of negatively charged particles. Finally, in 1897 Joseph John Thomson and the German physicist Emil Wiechert (1861 -1928) independently from each other to determine the ratio of the electron charge to its mass, conclusively prove its existence.

Wilhelm Conrad Röntgen (1845 -1923) discovered in 1895 that the fall of the cathode ray anode, a new type of radiation - X-rays (X-rays), which have a high penetrating power and cause fluorescence various substances. The nature of X-rays also initially interpreted in different ways - in addition to the view that the X-rays are similar to ultraviolet light, and expressed their assumptions about the corpuscular nature. Finally, the wave nature of X -rays has been proven only in 1913, when Max Theodor Felix von Laue (1879 -1960) discovered them during the passage of the diffraction through crystals (a consequence of this discovery was the emergence of a fundamentally New research method - X-ray analysis, which allows experimentally determine the molecular and crystal structure substances).

In 1897 -1898 gg. French scientists Pierre Curie (1859 -1906) and Mary Sklodowska-Curie (18671934) found that the emission of radiation of uranium is a property of an atom of uranium; This property does not depend on the order in which connection is uranium. In 1898, the Curies discovered that the same is true of the other element - thorium. In the same year they started research Bohemian pitchblende - one of the natural minerals uranium emits a stronger radiation (Curies proposed the term radioactivity) than pure uranium salts. The result was the discovery of two new radioactive elements polonium and radium.

In 1899, Henri Becquerel and the English physicist Ernest Rutherford (1871 -1937) found heterogeneity of uranium radiation: in a magnetic field rays divided so that there are two components, corresponding flux of particles with positive and negative charges. Paul Villard (1860 -1934) in 1900 identified another type: the rays do not deviate magnetic field. Rutherford suggested denote these radiation first letters of the Greek alphabet: alpha, beta and gamma rays. Becquerel showed that β-rays deflected by the magnetic field in the same direction and by the same amount, as cathode rays, and therefore represent the flow of electrons.

In 1900, Rutherford found that thorium compounds continuously emit radioactive gas - thorium emanation (radon), marking the beginning Research products of radioactive decay. In 1903 William Ramsay and Frederick Soddy (18771956) proved that the α-decay of radium produced helium. In the same year Rutherford and Frederick Soddy laid the foundations of theory of radioactive decay, showing that uranium, thorium and actinium are the ancestors of families radioactive elements, which are the products of their decomposition; end decay product is lead. As the most important characteristics radioactive elements were invited to the entered Pierre Curie concept half life.

Opening of the main components of the atom and the possibility of transmutation of elements (it turned out, the alchemists were not so not right in saying that the transmutation - only a matter of art!) led to radical revision of the structure of matter. alchemical term transmutation returned to science; now it has come to mean the conversion of atoms one chemical element into another as a result of radioactive decay of nuclei or nuclear reactions.