Here the differentiating electron is the electron that distinguishes an element from its predecessor. Thus, lanthanum, like scandium and yttrium, had a d- differentiating electron whereas lutetium had an f- differentiating electron. So cerium, as the first lanthanoid was f 1d 1s 2 ytterbium, as the penultimate lanthanoid, was thought to be f 13d 1s 2 and lutetium, as the last lanthanoid, f 14d 1s 2. In 1925, Goldschmidt proposed the name “lanthanide” for the elements cerium to lutetium, in reference to the similarity of their properties to lanthanum.Įarly spectroscopic work on lanthanum and the lanthanoids determined the ground state electron configuration of lanthanum was d 1s 2 and seemed to indicate that the following lanthanoids (cerium to lutetium) had, with few exceptions, an electronic configuration of the form f = 1–14, d 1s 2. Like lanthanum, it was regarded as one of the rare earth metals, these being a grouping of 14–16 (depending on the author) metals that also came to be associated with Group 3. Lanthanum subsequently came to be associated with Group 3, along with scandium and yttrium (Thyssen and Binnemans 2011, p. Mendeleev published his first periodic table in 1869. Other than to provide necessary context, I will not further revisit lutetium in Group 3 arguments. However, the trends involved apply regardless of whether lutetium is under Y or at the end of the f-block, after Yb. Unfortunately this argument introduces an anomaly in the overall regularity of term symbols.Īlvarez ( 2020) supports lutetium on the basis of trends in atomic size, coordination number, and relative abundance of metal–oxygen bonds. Tsimmerman and Boyce ( 2019) argued for lutetium in Group 3 on the basis of the regularity of spin multiplicity, which is one of the three components of an element’s spectrographic term symbol.
#Ca element group series#
The series starts with Ce 3+ as 4f 1 and concludes with Yb 3+ 4f 13 and Lu 3+ 4f 14. Thus, with lanthanum in Group 3, the number of f-electrons in the trivalent cations of the f-block elements corresponds perfectly with their position in that block.
Since ions are more important than isolated gaseous atoms for nearly all atoms, and important ions have no anomalous electron configurations, there is little reason to worry students with anomalous electron configurations of atoms: we prefer to teach ‘characteristic’ electron configurations without anomalies in the occupancies of d- and s-orbitals in the transition elements or d-, s-, and f- orbitals in the inner transition elements. …valence electron configurations of atoms and ions are also important in predicting the periodicity of chemical properties.
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