Jump to content

User:0JOTARO/Plum pudding model

From Wikipedia, the free encyclopedia

Article Draft

[edit]

Lead

[edit]

Article body

[edit]

Overview

[edit]

... the atoms of the elements consist of a number of negatively electrified corpuscles enclosed in a sphere of uniform positive electrification, ... Thomson's model was the first to assign a specific inner structure to an atom, the only downside being that it contained a lot of assumptions, and didn't have any mathematical evidence to back it up.[1][2]


Thomson attempted unsuccessfully to reshape his model to account for some of the major spectral lines experimentally known for several elements.

After the scientific discovery of radioactivity, Thomson decided to address it in his model by stating:

...we must face the problem of the constitution of the atom, and see if we can imagine a model which has in it the potentiality of explaining the remarkable properties shown by

radio-active substances...[3]


The main objective of Thomson's model after its initial release was to account for the electrically neutral and chemically varied, state of the atom.[4] the orbits of the electrons were stable under classical mechanics because when an electron moved away from the centre of the positively charged sphere, it was subjected to a greater net positive inward force, because there was more positive charge inside its orbit (see Gauss's law). Electrons were free to rotate in rings which were further stabilized by interactions among the electrons, and spectroscopic measurements were meant to account for energy differences associated with different electron rings. As for the properties of matter, Thomson believed that they arose from electrical effects. He further emphasized on the need of a theory to help picture the physical and chemical aspects of an atom using the theory of corpuscles and positive electricity(Positive charge).[5]

According to a centennial celebration of the Bohr atom in Nature magazine, it was John William Nicholson in 1912 who first discovered that electrons radiate the spectral lines as they descend towards the nucleus and his theory was both nuclear and quantum. Thomson's model changed over the course of its initial publication, finally becoming a model with much more mobility containing electrons revolving in the dense field of positive charge(Positive Electricity as called by Thomson) rather than the static "Plum-pudding" structure.[1]

References

[edit]
  1. ^ a b Hon, Giora; Goldstein, Bernard R. (2013). "J. J. Thomson's plum-pudding atomic model: The making of a scientific myth: J. J. Thomson's plum-pudding atomic model: The making of a scientific myth". Annalen der Physik. 525 (8–9): A129–A133. doi:10.1002/andp.201300732.
  2. ^ Thomson, J. J. (1899-12-01). "LVIII. On the masses of the ions in gases at low pressures". The London, Edinburgh, and Dublin Philosophical Magazine and Journal of Science. 48 (295): 547–567. doi:10.1080/14786449908621447. ISSN 1941-5982.
  3. ^ Thomson, J. J. (1904). Electricity and matter. Mrs. Hepsa Ely Silliman memorial lectures. New Haven: Yale University Press. ISBN 978-0-686-83533-2.
  4. ^ Thomson, J.J. (1904-03-01). "XXIV. On the structure of the atom: an investigation of the stability and periods of oscillation of a number of corpuscles arranged at equal intervals around the circumference of a circle; with application of the results to the theory of atomic structure". The London, Edinburgh, and Dublin Philosophical Magazine and Journal of Science. 7 (39): 237–265. doi:10.1080/14786440409463107. ISSN 1941-5982.
  5. ^ R., E. (1908). "The Corpuscular Theory of Matter". Nature. 77 (2005): 505–506. doi:10.1038/077505a0. ISSN 1476-4687.