English Dictionary: protactinium | by the DICT Development Group |
2 results for protactinium | |
From WordNet (r) 3.0 (2006) [wn]: | |
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From The Elements (22Oct97) [elements]: | |
protactinium Symbol: Pa Atomic number: 91 Atomic weight: (231) Radioactive metallic element, belongs to the actinoids. The most stable isotope, Pa-231 has a half-life of 2.43*10^4 years. At least 10 other radioactive isotopes are known. No practical applications are known. Discovered in 1917 by Lise Meitner and Otto Hahn. |