On the Folder tab, in the Properties group, click Folder Properties. On the Outlook Address Book tab, clear the Show this folder as an e-mail Address Book check box. If you want to turn Suggested Contacts off, do the following: Click the File tab.
Best Answer: U-238 is by far the most common isotope of Uranium found naturally, 99.284%. It has 238 nucleons, 92 of which are protons. The remaining 146 are neutrons. U-235, which accounts for 0.711% of all Uranium found naturally, is the useful one for fission reactors (and bombs), has 235 - 92 = 143 neutrons. U-234 is also found in extremely small quantities, 0.0058%, and has 142 neutrons.
Scientists knew that the most common isotope, uranium 238, was not suitable for a nuclear weapon. There is a fairly high probability that an incident neutron would be captured to form uranium 239 instead of causing a fission.However, uranium 235 has a high fission probability.Of natural uranium, only 0.7% is uranium 235. This meant that a large amount of uranium was needed to obtain the necessary quantities of uranium 235.owever, uranium 235 has a high fission probability. Of natural uranium, only 0.7% is uranium 235. This meant that a large amount of uranium was needed to obtain the necessary quantities of uranium 235.