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The electronic configuration of most neutral gas-phase lanthanide atoms is [Xe]6s 2 4f n, where n is 56 less than the atomic number Z. Exceptions are La, Ce, Gd, and Lu, which have 4f n −1 5d 1 (though even then 4f n is a low-lying excited state for La, Ce, and Gd; for Lu, the 4f shell is already full, and the fifteenth electron has no choice ...
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.
(Europium and ytterbium have lower melting points because they delocalise about two electrons per atom rather than three.) [24] This chemical availability of f orbitals justifies lanthanum's placement in the f-block despite its anomalous ground-state configuration [25] [26] (which is merely the result of strong interelectronic repulsion making ...
Configurations of elements 109 and above are not available. Predictions from reliable sources have been used for these elements. Grayed out electron numbers indicate subshells filled to their maximum. Bracketed noble gas symbols on the left represent inner configurations that are the same in each period. Written out, these are: He, 2, helium : 1s 2
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.
The lanthanide contraction is the greater-than-expected decrease in atomic radii and ionic radii of the elements in the lanthanide series, from left to right. It is caused by the poor shielding effect of nuclear charge by the 4f electrons along with the expected periodic trend of increasing electronegativity and nuclear charge on moving from left to right.
Because of its closed-shell electron configuration, its density, melting point and boiling point are much lower than those of most other lanthanides. In 1878, Swiss chemist Jean Charles Galissard de Marignac separated from the rare earth "erbia" (another independent component) which he called " ytterbia ", for Ytterby , the village in Sweden ...
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