More than 99%of naturally occurring uranium is U-238. The valuable U-235 makes up less than 1% of uranium, and must be "enriched" in complicated processes.
The most common isotope of uranium is uranium-238.
The most abundant isotope of arsenic is arsenic-75.
The most common isotope of uranium is uranium-238 with 146 neutrons.
Has had most of the uranium-235 (an isotope of uranium)) separated out of it.
It is impossible to know exactly this value; probably approx. 5.109 tons. But only a very small part of this quantity is economically to extract today.
Francium has no stable isotopes. That means it doesn't really have a "most abundant" isotope; they're all pretty much nonexistent. There are trace amounts of 223Fr in uranium minerals, because it's a decay product of 227Ac (which is itself a decay product in the decay chain of uranium).
There is no uranium isotope with 234 neutrons. The questioner almost certainly meant the uranium isotope with 234 nucleons, which is a naturally occurring isotope U234 otherwise element 92, with 142 neutrons.In which case its half life would be 252,000 years.
The most common isotope of uranium is uranium-238.
The most abundant isotope of arsenic is arsenic-75.
The most common isotope of uranium is uranium-238 with 146 neutrons.
Tritium is the most abundant hydrogen isotope
The most common natural isotope is 238U: 99,2742 %.
Has had most of the uranium-235 (an isotope of uranium)) separated out of it.
It is impossible to know exactly this value; probably approx. 5.109 tons. But only a very small part of this quantity is economically to extract today.
Uranium-238 has 146 neutrons.
Uranium consists primarily of two isotopes: uranium-235 and uranium-238. These isotopes are naturally occurring and are radioactive. Uranium-235 is the more fissile isotope for nuclear reactions, while uranium-238 is more abundant but less reactive.
Uranium 235 is the most important isotope of uranium; it is a fissionable isotope used in HWR, PWR, BWR, research reactors and other types of reactors. But it is rare, only 0.72% of natural Uranium is this isotope.The more plentiful Uranium 238 isotope is only fertile not fissionable; it can only be used in fast reactors to breed Plutonium, which is fissionable. Isotopes of plutonium 239Pu and 241Pu are highly fissionable and importants for nuclear fuels.