翻訳と辞書 Words near each other ・ Isotopes of krypton ・ Isotopes of lanthanum ・ Isotopes of lawrencium ・ Isotopes of lead ・ Isotopes of lithium ・ Isotopes of livermorium ・ Isotopes of lutetium ・ Isotopes of magnesium ・ Isotopes of manganese ・ Isotopes of meitnerium ・ Isotopes of mendelevium ・ Isotopes of mercury ・ Isotopes of molybdenum ・ Isotopes of neodymium ・ Isotopes of neon ・ Isotopes of neptunium ・ Isotopes of nickel ・ Isotopes of niobium ・ Isotopes of nitrogen ・ Isotopes of nobelium ・ Isotopes of osmium ・ Isotopes of oxygen ・ Isotopes of palladium ・ Isotopes of phosphorus ・ Isotopes of platinum ・ Isotopes of plutonium ・ Isotopes of polonium ・ Isotopes of potassium ・ Isotopes of praseodymium ・ Isotopes of promethium Dictionary Lists mini英和辞書 mini和英辞書 Webster 1913 Latin-English FOLDOC Wikipedia English ウィキペディア

翻訳と辞書　辞書検索 [ 開発暫定版 ] スポンサード リンク Isotopes of neptunium ： ウィキペディア英語版 Isotopes of neptunium Neptunium (Np) is an artificial element, and thus a standard atomic mass cannot be given. Like all artificial elements, it has no stable isotopes. The first isotope to be synthesized was 239Np in 1940, produced by bombarding 238U with neutrons to produce 239U, which then underwent beta decay to 239Np. Trace quantities are found in nature from neutron capture by uranium atoms. Twenty neptunium radioisotopes have been characterized, with the most stable being with a half-life of 2.14 million years, with a half-life of 154,000 years, and with a half-life of 396.1 days. All of the remaining radioactive isotopes have half-lives that are less than 4.5 days, and the majority of these have half-lives that are less than 50 minutes. This element also has 4 meta states, with the most stable being (t1/2 22.5 hours). The isotopes of neptunium range in atomic weight from 225.0339 u () to 244.068 u (). The primary decay mode before the most stable isotope, , is electron capture (with a good deal of alpha emission), and the primary mode after is beta emission. The primary decay products before are isotopes of uranium and protactinium, and the primary products after are isotopes of plutonium. ==Some notable isotopes== 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Isotopes of neptunium」の詳細全文を読む スポンサード リンク 翻訳と辞書 : 翻訳のためのインターネットリソース Copyright(C) kotoba.ne.jp 1997-2016. All Rights Reserved.