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The atomic nucleus shown expanded more than 10,000 times its size relative to the atom; electrons have no measurable diameter. 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.
The atomic nucleus is the small, dense region consisting of protons and neutrons at the center of an atom, discovered in 1911 by Ernest Rutherford based on the 1909 Geiger–Marsden gold foil experiment.
Otto Robert Frisch was born in Vienna in 1904 to a Jewish family, the son of Justinian Frisch, a painter, and Auguste Meitner Frisch, a concert pianist. [4] He himself was talented at both but also shared his maternal aunt Lise Meitner's love of physics and commenced a period of study at the University of Vienna, graduating in 1926 with some work on the effect of the newly discovered electron ...
On April 30, John Cockcroft and Ernest Walton publish the first disintegration of an atomic nucleus, popularly described as splitting the atom. They report the production of two alpha particles from the bombardment of lithium-7 nuclei by protons, using a Cockcroft–Walton generator at the University of Cambridge 's Cavendish Laboratory . [ 7 ]
The first two reactions that the Berlin group had observed were light elements created by the breakup of uranium nuclei; the third, the 23-minute one, was a decay into the real element 93. [103] On returning to Copenhagen, Frisch informed Bohr, who slapped his forehead and exclaimed "What idiots we have been!"
The definition by the IUPAC/IUPAP Joint Working Party (JWP) states that a chemical element can only be recognized as discovered if a nucleus of it has not decayed within 10 −14 seconds. This value was chosen as an estimate of how long it takes a nucleus to acquire electrons and thus display its chemical properties. [15] [d]
If two elements can form two compounds, the first compound is a binary compound and the second is a "ternary compound" consisting of one atom of the first element and two of the second. If two elements can form three compounds between them, then the third compound is a "quaternary" compound containing one atom of the first element and three of ...
The number of protons in an atom (which Rutherford called the "atomic number" [27] [28]) was found to be equal to the element's ordinal number on the periodic table and therefore provided a simple and clear-cut way of distinguishing the elements from each other. The atomic weight of each element is higher than its proton number, so Rutherford ...