Dutch scientist Antonius Van den Broek
In 1914, the disposal of physicists and chemists came direct way to determine the position of the element in the periodic table - Henry Gwyn English physicist Moseley Jeffries found that the root of the frequency characteristic X-ray radiation is linearly related to the integer value - the atomic number, which coincides with the item number in the periodic table. The law allowed Moseley to experimentally confirm correct positioning of elements, including radioactive isotopes in the periodic table, also confirmed the validity of the retreat in some cases the order of items on the order of increasing atomic mass (the so-called anomalies in the periodic table). That is the atomic number, which coincides, as suggested by the Dutch scientist Antonius Van den Broek, with the magnitude of the positive charge on the nucleus of the atom, became the basis for classification of chemical elements. In 1920 the English physicist James Chadwick experimentally determined the nuclear charge of copper silver and platinum, obtaining for them the values of 29.3, 46.3 and 77.4, respectively, which almost coincided with their atomic numbers 29, 47 and 78.
Rutherford in 1911 proposed his nuclear model of the atom in the center of the atom is positively charged nucleus, whose volume is negligible compared to the size of an atom, electrons revolve around the nucleus, which number approximately equal to half the atomic mass of an element. Rutherford's atomic model with the undoubted merits contain important contradiction: in accordance with the laws of classical electrodynamics, an electron orbiting the nucleus should continuously emit electromagnetic radiation, losing energy. As a result, the radius of the electron orbit would decrease rapidly, and calculated from these views, the lifetime of the atom is negligible. However, Rutherford model was the basis for a fundamentally new theory, developed in 1913 by Danish physicist Niels Henrik David Bohr.
Thank you for taking the time to read my work!the table can say this-there are elements in accordance withthe number of protons and neutrons, and because Element 71 is located in all cellsthe long version of the table and to place the following in accordance with lanthanides and also the periodic law is needed in this table to put down some new elements with the numbers 72,73,74,75. here and suspicion.with atomic weights of all convergent but the number of protons and neutrons may be different.
Each subsequent element is different from the previous view that its nucleus the number of protons increases by one, and the number of neutrons increases, in the general case for a few. That is, the kernel is always more neutrons than protons (not counting the very light nuclei). In the literature it is strange the ratio of neutrons to the number of protons, for any kernel, nothing is explained. To build a model of atomic nuclei we note that while the alpha radioactivity of helium nuclei have approximately equal energy. Therefore, on the outer envelope of the kernel will place all of the protons with the same number of neutrons, ie at one energy level can only bosons, which located on the outer envelope of the nucleus and the alpha particles are. Inside the nucleus putting the remaining neutrons, whose task will be the weakening of electrostatic repulsion of protons fields. Assuming a spherical nucleus, and the radii of protons and neutrons of about the same, for any element was the kernel model to explain the ratio of neutrons to the number of protons, derived from the package kernel atom nucleons. (Mismatch 0-10%). Radioactive decay is probably associated with the compression of the nucleus, because with the growth of the sequence number of neutrons an element of the kernel becoming increasingly weakened radial repulsive force of protons. If the mass of the nucleus to take primary and secondary chemical properties of the atom, the table of elements atomic weight should be monotonically changed, both horizontally and vertically. Building the table on these grounds, we are forced, after lutetium and Lawrence left four empty seats, so that the chemical properties of elements. Perhaps, at the opening of the need to become the definition of the charge of the nucleus! (Charge of the nucleus is determined only for copper and platinum).