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Neptunium-235 has 142 neutrons and a half-life of 396.1 days. This isotope decays by: Alpha emission: the decay energy is 5.2 MeV and the decay product is protactinium-231. Electron capture: the decay energy is 0.125 MeV and the decay product is uranium-235; This isotope of neptunium has a weight of 235.044 063 3 u.
Radioactive isotope table "lists ALL radioactive nuclei with a half-life greater than 1000 years", incorporated in the list above. The NUBASE2020 evaluation of nuclear physics properties F.G. Kondev et al. 2021 Chinese Phys. C 45 030001. The PDF of this article lists the half-lives of all known radioactives nuclides.
The isotope tables given below show all of the known isotopes of the chemical elements, arranged with increasing atomic number from left to right and increasing neutron number from top to bottom. Half lives are indicated by the color of each isotope's cell (see color chart in each section).
Actinium-225 has a half-life of 10 days and decays by alpha emission. It is part of the neptunium series, for it arises as a decay product of neptunium-237 and its daughters such as uranium-233 and thorium-229. It is the last nuclide in the chain with a half-life over a day until the penultimate product, bismuth-209 (half-life 2.01 × 10 19 ...
Neptunium-237 is the most commonly synthesized isotope due to it being the only one that both can be produced via neutron capture and also has a half-life long enough to allow weighable quantities to be easily isolated. It is by far the most common isotope to be utilized in chemical studies of the element.
At least 3,300 nuclides have been experimentally characterized [1] (see List of radioactive nuclides by half-life for the nuclides with decay half-lives less than one hour). A nuclide is defined conventionally as an experimentally examined bound collection of protons and neutrons that either is stable or has an observed decay mode .
The single-row parameters, commented "!"=could be required; ..1 – 4 refer to the decay mode dm#= {{Isotopes/main/isotope | mn =! massnumber | sym =! symbol | link = isotope page: uranium-232 | ref = reference for the isotope-row | na =! natural abundancy (can be: synth, trace) | hl =! half-life (can be: stable) | dm1 =! decay mode #1 ...
Half-life (symbol t ½) is the time required for a quantity (of substance) to reduce to half of its initial value.The term is commonly used in nuclear physics to describe how quickly unstable atoms undergo radioactive decay or how long stable atoms survive.