57
La
138.905
Lantan
Engelska: Lanthanum
Lantanoid
Grupp 3
Period 6
Block d
Lantan är ett kemiskt grundämne i det periodiska systemet med kemisk beteckningen La och atomnummer 57 med en atomvikt på 138.905 u och klassas som lantanoid och ingår i grupp 3 (scandiumgruppen). Lantan är fast vid rumstemperatur.
Lantan i det periodiska systemet
| Tecken | La |
| Atomnummer | 57 |
| Grupp | 3 (Scandiumgruppen) |
| Period | 6 |
| Block | d |
| Ämnesklass | Lantanoid |
| Utseende | Silvery white |
| Färg | Silver |
| Antal protoner | 57 p+ |
| Antal neutroner | 82 n0 |
| Antal elektroner | 57 e- |
Från Wikipedia, den fria encyklopedinLantan är ett grundämne och en lantanoid, och tillhör de sällsynta jordartsmetallerna. Dessa metaller har en stor efterfrågan inom bland annat elektronikindustrin.
Fysikaliska egenskaper
| Fas vid STP | Fast |
| Densitet | 6.162 g/cm3 |
| Relativ atommassa | 138.905 u |
Thermal properties
| Smältpunkt | 1193 K 919.85 °C 1687.73 °F |
| Kokpunkt | 3737 K 3463.85 °C 6266.93 °F |
| Ångbildningsvärme | 399.57 kJ/mol |
Atomära egenskaper
| Elektronegativitet (Paulingskalan) | 1.1 |
| Elektronaffinitet | 53 kJ/mol |
| Oxidationstal | 0, +1, +2, +3 (a strongly basic oxide) |
| Jonisationspotential |
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Elektronkonfiguration för lantan
Elektronkonfiguration Kortfattad konfiguration | [Xe] 5d1 6s2 | ||||||||||||||||||||||||||||||||||||||||||||||
| Full konfiguration | 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 5s2 5p6 5d1 6s2 | ||||||||||||||||||||||||||||||||||||||||||||||
Elektronkonfigurationsdiagram |
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| Elektroner per skal | 2, 8, 18, 18, 9, 2 | ||||||||||||||||||||||||||||||||||||||||||||||
| Outer shell electrons | 2 | ||||||||||||||||||||||||||||||||||||||||||||||
| Valency-elektroner | 3 | ||||||||||||||||||||||||||||||||||||||||||||||
| Bohrs atommodell | Figur: Skaldiagram över Lantan (La) atom. | ||||||||||||||||||||||||||||||||||||||||||||||
Orbitaldiagram |
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The history of Lanthanum
| Upptäckt | Carl Gustaf Mosander (1838) |
| Namngivare | Carl Gustaf Mosander (1839) |
Upptäckten av lantan In 1751, the Swedish mineralogist Axel Fredrik Cronstedt discovered a heavy mineral from the mine at Bastnäs, later named cerite. Thirty years later, the fifteen-year-old Wilhelm Hisinger, from the family owning the mine, sent a sample of it to Carl Scheele, who did not find any new elements within. In 1803, after Hisinger had become an ironmaster, he returned to the mineral with Jöns Jacob Berzelius and isolated a new oxide which they named ceria after the dwarf planet Ceres, which had been discovered two years earlier. Ceria was simultaneously independently isolated in Germany by Martin Heinrich Klaproth. Between 1839 and 1843, ceria was shown to be a mixture of oxides by the Swedish surgeon and chemist Carl Gustaf Mosander, who lived in the same house as Berzelius and studied under him: he separated out two other oxides which he named lanthana and didymia. He partially decomposed a sample of cerium nitrate by roasting it in air and then treating the resulting oxide with dilute nitric acid. That same year, Axel Erdmann, a student also at the Karolinska Institute, discovered lanthanum in a new mineral from Låven island located in a Norwegian fjord. Finally, Mosander explained his delay, saying that he had extracted a second element from cerium, and this he called didymium. Although he didn't realise it, didymium too was a mixture, and in 1885 it was separated into praseodymium and neodymium. Since lanthanum's properties differed only slightly from those of cerium, and occurred along with it in its salts, he named it from the Ancient Greek λανθάνειν [lanthanein] (lit. to lie hidden). Relatively pure lanthanum metal was first isolated in 1923. | |
| Original word | lanthanein |
| Language of origin | Greek |
| Name source | Egenskaper |
| Meaning | “Lie hidden” |
Naming The name comes from the Greek 'lanthanein', meaning to lie hidden, because the element was discovered hidden inside what was thought to be pure cerium oxide. | |