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The Rutherford model is a name for the first model of an atom with a compact nucleus. The concept arose from Ernest Rutherford discovery of the nucleus. Rutherford directed the Geiger–Marsden experiment in 1909, which showed much more alpha particle recoil than J. J. Thomson's plum pudding model of the atom could explain. Thomson's model had ...
In a 1913 paper, Rutherford declared that the "nucleus" (as he now called it) was indeed positively charged, based on the result of experiments exploring the scattering of alpha particles in various gases. [42] In 1917, Rutherford and his assistant William Kay began exploring the passage of alpha particles through gases such as hydrogen and ...
Hydrogen was known to be the lightest element, and its nuclei presumably the lightest nuclei. Now, because of all these considerations, Rutherford decided that a hydrogen nucleus was possibly a fundamental building block of all nuclei, and also possibly a new fundamental particle as well, since nothing was known to be lighter than that nucleus.
The diameter of the nucleus is in the range of 1.70 fm (1.70 × 10 −15 m [7]) for hydrogen (the diameter of a single proton) to about 11.7 fm for uranium. [8] These dimensions are much smaller than the diameter of the atom itself (nucleus + electron cloud), by a factor of about 26,634 (uranium atomic radius is about 156 pm ( 156 × 10 −12 m ...
The word proton is Greek for "first", and the name was given to the hydrogen nucleus by Ernest Rutherford in 1920. In previous years, Rutherford had discovered that the hydrogen nucleus (known to be the lightest nucleus) could be extracted from the nuclei of nitrogen by atomic collisions. [10]
Rutherford defined this position as being the element's atomic number. [73] [74] [75] In 1913, Henry Moseley measured the X-ray emissions of all the elements on the periodic table and found that the frequency of the X-ray emissions was a mathematical function of the element's atomic number and the charge of a hydrogen nucleus (see Moseley's law).
A schematic of the nucleus of an atom indicating β − radiation, the emission of a fast electron from the nucleus (the accompanying antineutrino is omitted). In the Rutherford model for the nucleus, a red sphere was a proton with positive charge, and a blue sphere was a proton tightly bound to an electron, with no net charge.
These observations led Rutherford to conclude that the hydrogen nucleus is a singular particle with a positive charge equal to the electron's negative charge. [25] He named this particle " proton " in 1920. [ 26 ]