Isotopes - Douwei

Nuclear species with the same number of protons in their nuclei but different numbers of neutrons are called isotopes. Because they have the same number of protons, they have the same atomic number and occupy the same position in the periodic table of elements. They are also called isotopes. The name comes from the Greek words isos (same) and topos (place). Among isotopes, those that undergo radioactive decay are called radioisotopes (RI), and those that are stable are called stable isotopes. Radioactive isotopes were discovered in 1906, when BB Boltwood found that ionium Io ( ^233Th ) has the same properties as tritium. The first stable isotopes were discovered in 1912, when JJ Thomson discovered the neon isotopes ^20Ne and ^22Ne through anode ray analysis. Although isotopes have almost the same chemical properties, differences in mass number, nuclear shape, size, spin, etc. result in differences in chemical behavior.

Source: Morikita Publishing "Chemical Dictionary (2nd Edition)" Information about the Chemical Dictionary 2nd Edition

原子核中の陽子の数は同じであるが，中性子の数が異なる核種を互いに同位体という．陽子の数が同じなので同じ原子番号をもち，元素の周期表では同じ位置を占める．同位元素あるいはアイソトープともいう．ギリシア語のisos(同じ)とtopos(場所)に由来する．同位体のうち，放射性崩壊するものを放射性同位体(ラジオアイソトープ，RI)，安定なものを安定同位体という．放射性同位体の発見は，1906年，B.B. Boltwoodが，イオニウムIo(²³³Th)がトリチウムと同じ性質をもつことを見いだしたことによる．安定同位体は，1912年，J.J. Thomsonが陽極線分析において，ネオンの同位体 ²⁰Ne，²²Ne を発見したのが最初である．同位体どうしの化学的性質はほぼ同じだが，質量数，原子核の形，サイズ，スピンなどが異なることによって化学的挙動に差が現れる．

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