Nuclides with atomic number of 11 but with different mass numbers
There are 20 isotopes of sodium (11Na), ranging from 17 Na to 39 Na (except for the still-unknown 36Na and 38Na),[4] and two isomers (22m Na and 24m Na). 23 Na is the only stable (and the only primordial) isotope. It is considered a monoisotopic element and it has a standard atomic weight of 22.98976928(2). Sodium has two radioactivecosmogenic isotopes (22 Na, with a half-life of 2.6019(6) years;[nb 1] and 24Na, with a half-life of 14.9560(15) h). With the exception of those two isotopes, all other isotopes have half-lives under a minute, most under a second. The shortest-lived is the unbound 18 Na, with a half-life of 1.3(4)×10−21 seconds (although the half-life of the similarly unbound 17Na is not measured).
Acute neutron radiation exposure (e.g., from a nuclear criticality accident) converts some of the stable 23 Na (in the form of Na+ ion) in human blood plasma to 24 Na. By measuring the concentration of this isotope, the neutron radiation dosage to the victim can be computed.
22 Na is a positron-emitting isotope with a remarkably long half-life. It is used to create test-objects and point-sources for positron emission tomography.
^( ) – Uncertainty (1σ) is given in concise form in parentheses after the corresponding last digits.
^# – Atomic mass marked #: value and uncertainty derived not from purely experimental data, but at least partly from trends from the Mass Surface (TMS).
^ a b# – Values marked # are not purely derived from experimental data, but at least partly from trends of neighboring nuclides (TNN).
^Modes of decay:
^Bold symbol as daughter – Daughter product is stable.
^( ) spin value – Indicates spin with weak assignment arguments.
^Decay mode shown has been observed, but its intensity is not known experimentally.
Sodium-23 is an isotope of sodium with an atomic mass of 22.98976928. It is the only stable isotope of sodium and also the only primordial isotope. Because of its abundance, sodium-23 is used in nuclear magnetic resonance in various research fields, including materials science and battery research.[7] Sodium-23 relaxation has applications in studying cation-biomolecule interactions, intracellular and extracellular sodium, ion transport in batteries, and quantum information processing.[8]
Sodium-24
Sodium-24 is radioactive and can be created from common sodium-23 by neutron activation. With a half-life of 14.9560(15) h, 24 Na decays to 24Mg by emission of an electron and two gamma rays.[9][10]
Exposure of the human body to intense neutron radiation creates 24 Na in the blood plasma. Measurements of its quantity can be done to determine the absorbed radiation dose of a patient.[10] This can be used to determine the type of medical treatment required.
When sodium is used as coolant in fast breeder reactors, 24 Na is created, which makes the coolant radioactive. When the 24 Na decays, it causes a buildup of magnesium in the coolant. Since the half-life is short, the 24 Na portion of the coolant ceases to be radioactive within a few days after removal from the reactor. Leakage of the hot sodium from the primary loop may cause radioactive fires,[11] as it can ignite in contact with air (and explodes in contact with water). For this reason the primary cooling loop is within a containment vessel.
Sodium has been proposed as a casing for a salted bomb, as it would convert to 24 Na and produce intense gamma-ray emissions for a few days.[12][13]
Notes
^ a bNote that NUBASE2020 uses the tropical year to convert between years and other units of time, not the Gregorian year. The relationship between years and other time units in NUBASE2020 is as follows: 1 y = 365.2422 d = 31 556 926 s
References
^ a b c dKondev, F. G.; Wang, M.; Huang, W. J.; Naimi, S.; Audi, G. (2021). "The NUBASE2020 evaluation of nuclear properties" (PDF). Chinese Physics C. 45 (3): 030001. doi:10.1088/1674-1137/abddae.
^Prohaska, Thomas; Irrgeher, Johanna; Benefield, Jacqueline; Böhlke, John K.; Chesson, Lesley A.; Coplen, Tyler B.; Ding, Tiping; Dunn, Philip J. H.; Gröning, Manfred; Holden, Norman E.; Meijer, Harro A. J. (2022-05-04). "Standard atomic weights of the elements 2021 (IUPAC Technical Report)". Pure and Applied Chemistry. doi:10.1515/pac-2019-0603. ISSN 1365-3075.
^ a bAhn, D.S.; et al. (2022-11-14). "Discovery of 39Na". Physical Review Letters. 129 (21) 212502: 212502. Bibcode:2022PhRvL.129u2502A. doi:10.1103/PhysRevLett.129.212502. PMID 36461972. S2CID 253591660.
^Wang, Meng; Huang, W.J.; Kondev, F.G.; Audi, G.; Naimi, S. (2021). "The AME 2020 atomic mass evaluation (II). Tables, graphs and references*". Chinese Physics C. 45 (3): 030003. doi:10.1088/1674-1137/abddaf.
^ a bEkendahl, Daniela; Rubovič, Peter; Žlebčík, Pavel; Hupka, Ivan; Huml, Ondřej; Bečková, Věra; Malá, Helena (7 November 2019). "Neutron dose assessment using samples of human blood and hair". Radiation Protection Dosimetry. 186 (2–3): 202–205. doi:10.1093/rpd/ncz202. PMID 31702764.
^Unusual occurrences during LMFR operation, Proceedings of a Technical Committee meeting held in Vienna, 9–13 November 1998, IAEA. Pages 84, 122.
^"Science: fy for Doomsday". Time. November 24, 1961. Archived from the original on March 14, 2016.
^Clark, W. H. (1961). "Chemical and Thermonuclear Explosives". Bulletin of the Atomic Scientists. 17 (9): 356–360. Bibcode:1961BuAtS..17i.356C. doi:10.1080/00963402.1961.11454268.
External links
Sodium isotopes data from The Berkeley Laboratory Isotopes Project's