Atomic nucleus

A model of an atomic nucleus showing it as a compact bundle of protons (red) and neutrons (blue), the two types of nucleons. In this diagram, protons and neutrons look like little balls stuck together, but an actual nucleus (as understood by modern nuclear physics) cannot be explained like this, but only by using quantum mechanics. In a nucleus that occupies a certain energy level (for example, the ground state), each nucleon can be said to occupy a range of locations.
Nuclear physics
Models of the nucleus
Nuclides' classification
Nuclear stability
Radioactive decay
Nuclear fission
Capturing processes
High-energy processes
Nucleosynthesis and
nuclear astrophysics
High-energy nuclear physics
Scientists

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. After the discovery of the neutron in 1932, models for a nucleus composed of protons and neutrons were quickly developed by Dmitri Ivanenko[1] and Werner Heisenberg.[2][3][4][5][6] An atom is composed of a positively charged nucleus, with a cloud of negatively charged electrons surrounding it, bound together by electrostatic force. Almost all of the mass of an atom is located in the nucleus, with a very small contribution from the electron cloud. Protons and neutrons are bound together to form a nucleus by the nuclear force.

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))[9] to about 60,250 (hydrogen atomic radius is about 52.92 pm).[a]

The branch of physics involved with the study and understanding of the atomic nucleus, including its composition and the forces that bind it together, is called nuclear physics.

  1. ^ Iwanenko, D. (1932). "The Neutron Hypothesis". Nature. 129 (3265): 798. Bibcode:1932Natur.129..798I. doi:10.1038/129798d0. ISSN 0028-0836. S2CID 4096734.
  2. ^ Heisenberg, W. (1932). "Über den Bau der Atomkerne. I". Z. Phys. 77 (1–2): 1–11. Bibcode:1932ZPhy...77....1H. doi:10.1007/BF01342433. S2CID 186218053.
  3. ^ Heisenberg, W. (1932). "Über den Bau der Atomkerne. II". Z. Phys. 78 (3–4): 156–164. Bibcode:1932ZPhy...78..156H. doi:10.1007/BF01337585. S2CID 186221789.
  4. ^ Heisenberg, W. (1933). "Über den Bau der Atomkerne. III". Z. Phys. 80 (9–10): 587–596. Bibcode:1933ZPhy...80..587H. doi:10.1007/BF01335696. S2CID 126422047.
  5. ^ Miller, Arthur I., ed. (1995). Early quantum electrodynamics: a source book (1. paperback ed.). Cambridge: Cambridge Univ. Press. pp. 84–88. ISBN 978-0-521-56891-3.
  6. ^ Fernandez, Bernard; Ripka, Georges & Fernandez, Bernard (2012). "Nuclear Theory After the Discovery of the Neutron". Unravelling the mystery of the atomic nucleus: a sixty year journey, 1896-1956. New York, NY: Springer. p. 263. ISBN 978-1-4614-4180-9.
  7. ^ Castelvecchi, Davide (November 2019). "How big is the proton? Particle-size puzzle leaps closer to resolution". Nature. 575 (7782): 269–270. Bibcode:2019Natur.575..269C. doi:10.1038/d41586-019-03432-4. ISSN 0028-0836. PMID 31719693. S2CID 207938065.
  8. ^ Angeli, I.; Marinova, K.P. (January 2013). "Table of experimental nuclear ground state charge radii: An update" (PDF). Atomic Data and Nuclear Data Tables. 99 (1): 69–95. Bibcode:2013ADNDT..99...69A. doi:10.1016/j.adt.2011.12.006. Archived (PDF) from the original on December 3, 2021.
  9. ^ ""Uranium" IDC Technologies" (PDF). Archived (PDF) from the original on May 7, 2018. Retrieved May 7, 2018.


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