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Lanthanum is the first element and prototype of the lanthanide series. ... [15] The 57 electrons of a lanthanum atom are ... due to the electron configuration of ...
The term derives from lanthanum, first discovered in 1838, at that time a so-called new rare-earth element "lying hidden" or "escaping notice" in a cerium mineral, [12] and it is an irony that lanthanum was later identified as the first in an entire series of chemically similar elements and gave its name to the whole series.
Here [Ne] refers to the core electrons which are the same as for the element neon (Ne), the last noble gas before phosphorus in the periodic table. The valence electrons (here 3s 2 3p 3) are written explicitly for all atoms. Electron configurations of elements beyond hassium (element 108) have never been measured; predictions are used below.
For example, the electron configuration of the neon atom is 1s 2 2s 2 2p 6, meaning that the 1s, 2s, and 2p subshells are occupied by two, two, and six electrons, respectively. Electronic configurations describe each electron as moving independently in an orbital, in an average field created by the nuclei and all the other
In the periodic table, it appears between the lanthanides lanthanum to its left and praseodymium to its right, and above the actinide thorium. It is a ductile metal with a hardness similar to that of silver. [9] Its 58 electrons are arranged in the configuration [Xe]4f 1 5d 1 6s 2, of which the four outer electrons are valence electrons. [10]
Many textbooks however show group 3 as containing scandium, yttrium, lanthanum, and actinium, a format based on historically wrongly measured electron configurations: [4] Lev Landau and Evgeny Lifshitz already considered it to be "incorrect" in 1948, [5] but the issue was brought to a wide debate only in 1982 by William B. Jensen. [4]
Neutral praseodymium's 59 electrons are arranged in the configuration [Xe]4f 3 6s 2. Like most other lanthanides, praseodymium usually uses only three electrons as valence electrons, as the remaining 4f electrons are too strongly bound to engage in bonding: this is because the 4f orbitals penetrate the most through the inert xenon core of ...
The +2 state has a valence electron configuration of 4f 14 because the fully filled f-shell gives more stability. The yellow-green ytterbium(II) ion is a very strong reducing agent and decomposes water, releasing hydrogen , and thus only the colorless ytterbium(III) ion occurs in aqueous solution .