What is the atomic weight of uranium

The periodic table of the elements online

238U (uranium-238)

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Nuclide properties

146n   238U  
144n 234Th
Basic properties Mass number: 238 Number of neutrons: 146 Number of protons: 92 Energy level: 0 MeV Spin: 0    Mass and Energy: Atomic mass: 238.05078819 u Core mass: 238.00031884 u Mass excess: 47.3089 MeV Binding energy (total): 1801.69 MeV Binding energy (per u): 7.57 MeV    
Occurrence and distribution:Share in the isotope mixture*: 99.274 %Share universe:0.2 µg / kgShare of sun:0.986 µg / kgShare of earth envelope:3,177 mg / kgShare of earth's crust:2.68 mg / kg_______________
*Share in the natural isotope mixture of the isolable, stable or very long-lived element. The composition of the isotope mixture is stable within narrow limits for any location of the element.
Effective cross-sections:   σ (n, γ)2.68 barn  σ (n, f)3 μbarn  
Decay dates:   Half-life:4,468 billion years 17.1492 lg sSpecific decay constant (λ):4.916 •10-18 s-1Lifetime (τ):6.446 billion years Specific activity:12,439 MBq / kg
Type of decay:Probability:Daughter core:Energy emission: α 100 % 234Th 4.27 MeV Spontaneous split 5.5e-5%145Ba, 90Kr, 3n 165,479 MeV
Note on spontaneous splitting: The data are calculated under the assumption that daughter nuclei with 61% or 39% of the mass of the mother nucleus are created and 3 neutrons are released each time. This assumption corresponds to the statistically most common variant. Real fission takes place in a much more variable manner, both in terms of the size of the fragments and the number of neutrons released (up to 9).

swell for the mass defects and half-lives: http://www.nndc.bnl.gov/chart/. The Atomic masses correspond to the mass numbers in u minus the proportional mass defect. Core masses corresponds to atomic masses less the electron masses, whereby the binding energy of the electrons Not taken into account so that they deviate from the actual value by a few eV! The Half-lives are also literature values ​​from the named source. All other information (service life, decay constant) is calculated from them. The Decay energies are calculated from the differences in the masses of the particles involved in the decay; it is also done automatically by a script.