Uranium-240
Properties and data of the isotope 240U.
Uranium-240 is a radioisotope of the chemical element uranium, which has 148 neutrons in its atomic nucleus in addition to the element-specific 92 protons; the sum of the number of these atomic nucleus building blocks results in a mass number of 240. The very short-lived, only artificially produced, unstable and thus radioactive nuclide has no practical significance; the study of 240U is exclusively for academic purposes.
See also: List of individual Uranium isotopes (and general data sources).
General data
Name of the isotope:Uranium-240; U-240Symbol:240U or 24092UMass number A:240 (= number of nucleons)Atomic number Z:92 (= number of protons)Neutrons N:148Nucleon pairing (Z - N):even - evenNuclear ratio (N/Z ratio):1.6086956521739 (= neutron-proton ratio)Neutron excess (N-Z):56Isotopic mass:240.0565924(27) u (atomic weight of Uranium-240)Nuclide mass:240.0061297 u (calculated nuclear mass without electrons)Mass excess:52.71548 MeVMass defect:1.945718112 u (per nucleus)Nuclear binding energy:1812.42474702 MeV (per nucleus)
7.55176978 MeV (average binding energy per nucleon)Separation energy:SN = 5.9285(29) MeV (first neutron)
SP = 7.911(196) MeV (first proton)Half-life:14.1(1) hDecay constant λ:1.365538180772 × 10-5 s-1Specific activity α:3.426443030929 × 10+16 Bq g-1
926065.68403511 Ci g-1Spin and parity:
(nuclear angular momentum)0+Year of discovery:1953
Radioactive Decay
Half-life T½ = 14.1(1) h (hours) respectively 5.0760 × 104 seconds s.
Decay
mode | Daughter | Probability | Decay energy | γ energy
(intensity) |
|---|
| β- | 240Np | 100 % | 4.035(14) MeV | |
Parent Nuclides
Direct parent isotope is: 244Pu.
Isotones and Isobars
The following table shows the atomic nuclei that are isotonic (same neutron number N = 148) and isobaric (same nucleon number A = 240) with Uranium-240. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.
| Z | Isotone N = 148 | Isobar A = 240 |
|---|
| 90 | 238Th | |
| 91 | 239Pa | 240Pa |
| 92 | 240U | 240U |
| 93 | 241Np | 240Np |
| 94 | 242Pu | 240Pu |
| 95 | 243Am | 240Am |
| 96 | 244Cm | 240Cm |
| 97 | 245Bk | 240Bk |
| 98 | 246Cf | 240Cf |
| 99 | 247Es | 240Es |
| 100 | 248Fm | |
| 101 | 249Md | |
| 102 | 250No | |
| 103 | 251Lr | |
| 104 | 252Rf | |
External data and identifiers
Literature and References
[1] - B. Birkenbach et al.:
Spectroscopy of the neutron-rich actinide nucleus 240U following multinucleon-transfer reactions.
In: Physical Review C, 92, 044319, (2015), DOI 10.1103/PhysRevC.92.044319.
Last update: 2024-08-28
Perma link: https://www.chemlin.org/isotope/uranium-240
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