61
Pm
145
Prometium
Engelska: Promethium
Lantanoid
Period 6
Block f
Prometium är ett kemiskt grundämne i det periodiska systemet med kemisk beteckningen Pm och atomnummer 61 med en atomvikt på 145 u och klassas som lantanoid. Prometium är fast vid rumstemperatur.
Prometium i det periodiska systemet
| Tecken | Pm |
| Atomnummer | 61 |
| Grupp | - |
| Period | 6 |
| Block | f |
| Ämnesklass | Lantanoid |
| Utseende | Metallic |
| Färg | Silver |
| Antal protoner | 61 p+ |
| Antal neutroner | 84 n0 |
| Antal elektroner | 61 e- |
Från Wikipedia, den fria encyklopedinPrometium är ett metalliskt grundämne som tillhör lantanoiderna och de sällsynta jordartsmetallerna. Ämnet förekommer inte naturligt.
Fysikaliska egenskaper
| Fas vid STP | Fast |
| Densitet | 7.26 g/cm3 |
| Relativ atommassa | 145 u |
Thermal properties
| Smältpunkt | 1315 K 1041.85 °C 1907.33 °F |
| Kokpunkt | 3273 K 2999.85 °C 5431.73 °F |
| Ångbildningsvärme | 289 kJ/mol |
Atomära egenskaper
| Elektronegativitet (Paulingskalan) | 1.13 |
| Elektronaffinitet | 12.45 kJ/mol |
| Oxidationstal | +2, +3 (a mildly basic oxide) |
| Jonisationspotential |
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Elektronkonfiguration för prometium
Elektronkonfiguration Kortfattad konfiguration | [Xe] 4f5 6s2 | ||||||||||||||||||||||||||||||||||||||||||||||||
| Full konfiguration | 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 4f5 5s2 5p6 6s2 | ||||||||||||||||||||||||||||||||||||||||||||||||
Elektronkonfigurationsdiagram |
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| Elektroner per skal | 2, 8, 18, 23, 8, 2 | ||||||||||||||||||||||||||||||||||||||||||||||||
| Outer shell electrons | 2 | ||||||||||||||||||||||||||||||||||||||||||||||||
| Valency-elektroner | 3 | ||||||||||||||||||||||||||||||||||||||||||||||||
| Bohrs atommodell | Figur: Skaldiagram över Prometium (Pm) atom. | ||||||||||||||||||||||||||||||||||||||||||||||||
Orbitaldiagram
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The history of Promethium
| Upptäckt | Charles D. Coryell, Jacob A. Marinsky, Lawrence E. Glendenin (1945) |
| Namngivare | Grace Mary Coryell (1945) |
Upptäckten av prometium In 1902 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 1914 by Henry Moseley, who, having measured the atomic numbers of all the elements then known, found that atomic number 61 was missing. In 1926, 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 1938, 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. Promethium was first produced and characterized at Oak Ridge National Laboratory in 1945 by the separation and analysis of the fission products of uranium fuel irradiated in a graphite reactor. The discoverers proposed the name "prometheum" (the spelling was subsequently changed), derived from Prometheus, the Titan in Greek mythology who stole fire from Mount Olympus and brought it down to humans, to symbolize "both the daring and the possible misuse of mankind's intellect". However, a sample of the metal was made only in 1963. | |
| Original word | Prometheus |
| Language of origin | Greek |
| Name source | Mytologi |
| Meaning | “Prometheus” |
Naming The name is derived from Prometheus, the Greek Titan who stole fire from the gods, a nod to the fiery birth of the element from nuclear fission. | |