|MadSci Network: Physics|
References: Alberty, Physical Chemistry, 7ed., John Wiley; Chapter 12 atomic structure, or probably any college P. Chem. book Chemicalc, chemical concepts corporation, http://www.bizserv.com/c3 a program that gives a lot of elemental data. The periodic Table at http://www.webelements.com/ This is an interesting question and one that I have not thought about before. At first blush I will say that the answer is Yes and No. Yes, because the properties of an element are the sum of all the components of that atom and No because the physical and chemical properties of an element are determined mainly by the outer or valence electron configuration and the immediate inner electrons especially when d and f electrons are being added or have recently been added in the period of the Periodic Table. In order to explain the stability of the atom Niels Bohr modified the simple electrostatic approach to the atom and said that the electrons were present in the atom in discrete energy levels or orbitals. This approach allows an orbital radius and electron speed to be calculated for the H atom electron, however, that does not mean that the electron behaves so. The electron in an H atom has a speed according to those calculations of about 2e6 m/sec. Calculations for the heavier elements are doubtful but for a 1 electron atom of Z=100 the speed could be about 2e8 or 2/3 the speed of light, relativistic, but the electron is not going to weigh a ton. The picture this gives is of an electron in a high speed orbit to keep from falling into the nucleus. We know that this picture is incorrect. The electron, in falling into an orbital, emits the change in electrostatic energy as a photon. The picture is not one of conservation of energy as a falling baseball in a gravity field, but more like the baseball after it is caught and the PE to KE to heat and pain are completed and the surprise is still there. The electron is in its energy level and interacts minimally with the nucleus. It must interact because certain nuclei will capture a 1s electron [K capture]. The effects of increased electrostatic attraction are manifested in a smaller 1s orbital volume and shorter electron wavelength with increasing Z. This might manifest itself in changes in mass defect or possibly in K Xray emission for the heaviest elements; [this is pure conjecture on my part]. The Chemicalc program and the Web periodic table have graphs of many physical properties of the elements. These graphs show the periodic nature of these properties rather well. However, the periodicity does seem to break down or be more complicated for the heaviest elements. This is because the outer d and f filled orbitals are being pulled in closer to the nucleus as Z increases and their contribution to shielding increases rapidly with Z. This change in shielding affects the properties of the atoms and also lessens the effect of the nucleus. My conclusion is that the speed of the electrons cannot be described well and that the deep inner electrons after their shielding effect is considered have minimal to no effect on the chemical and physical properties of the bulk elements. I also discovered that there is a lot I do not understand about electrons in an atom and am open to additions or comments. Becoming a Mad Scientist, Jim Griepenburg. firstname.lastname@example.org
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