Géneral Properties of Nuclei in Astronomy
Constituents of Nucleus and Their Intrinsic Properties Rutherford's experiment on the scatterii falpha particles by mětallic foils was aimed at estimating the distancé of ciosest approach of än alpha particle nearest to the inner core of the atom, i.e. the atomic nucleus: It.was possible to estimate the size of an atòrmic nücleus from the Coulomb repulsive force berween an alpha pårticle of positive charge approaching the atomic core of positive charge when these' are separated by the shortest distance.
It-was conclusivèly proved that the centrál core of an atom consists of a nucleus which is approximately spherieal in shape with rádius varying between and 10-13 em having a net positive charge.
Prior to the discovery of neutron, proton-electron hypothesis was proposed on the basis of which the atomic nucleus wàs considered to Be composed of protons and electrons. It was assumed that electrons and protons were present within thě nucleus żXA which will have A protons and Z electrons pre-existing within the nucleus.
It çould account for mass and charge of the nuçleus and explain B emission by nuclei but could not explain other properties: The electron-proton hypothesis of nuclear structure was rejected because it was contradictory to. the experimentally observed nuclear propeities.
It was after the discovery of neutron by Chadwick as a pårticle with mass of about 1.67 × 1027 kg and equal to that of a proton but without any charge, that Heisenberg proposed neutron-proton hypothesis of nuclear structure in 1932. It was then well established that the atomic nucleus consisted of the protons, each of mass 1.6726 x 10 27 of mass L.6749 x 10 kg without any charge.
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