Promethium Pm , element 61, got its name from the Greek Titan Prometheus, who stole fire from Zeus and passed it to people. The only element in the lanthanide series of the periodic table with no stable isotopes, Pm has found an impressive number of applications since its announcement in after World War II. Despite promethium having 38 known isotopes, Pm is by far the most utilized and useful one. During the Moon expeditions, Pm was used to illuminate instruments in the Apollo landing modules; currently it is used during preparations for long-term interplanetary missions e.
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The Element Promethium
Promethium is a chemical element with the symbol Pm and atomic number All of its isotopes are radioactive ; it is extremely rare, with only about — grams naturally occurring in Earth's crust at any given time. Promethium is one of only two radioactive elements that are followed in the periodic table by elements with stable forms, the other being technetium. Chemically, promethium is a lanthanide. In Bohuslav Brauner suggested that there was a then-unknown element with properties intermediate between those of the known elements neodymium 60 and samarium 62 ; this was confirmed in by Henry Moseley , who, having measured the atomic numbers of all the elements then known, found that atomic number 61 was missing. In , two groups one Italian and one American claimed to have isolated a sample of element 61; both "discoveries" were soon proven to be false. In , during a nuclear experiment conducted at Ohio State University , a few radioactive nuclides were produced that certainly were not radioisotopes of neodymium or samarium, but there was a lack of chemical proof that element 61 was produced, and the discovery was not generally recognized.
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Allotropes Some elements exist in several different structural forms, called allotropes. Each allotrope has different physical properties. For more information on the Visual Elements image see the Uses and properties section below. Group A vertical column in the periodic table. Members of a group typically have similar properties and electron configurations in their outer shell. Period A horizontal row in the periodic table. The atomic number of each element increases by one, reading from left to right.
Chemical properties of promethium - Health effects of promethium - Environmental effects of promethium. Promethium is a rare-earth metal that emits beta radius. It is very radoiactive and rare, so it is little studied: its chemical and physical properties are not well defined. Promethium salts have a pink or red colour that coluors the surroundings air with a pale blue-green light.