Physicists have filled in some longtime blank spaces on the periodic table, calculating electron affinities of the lanthanides, a series of 15 elements known as rare earths.

It should have the electron configuration [Ar] 3d 9 4s 2. Instead, its 4s atomic orbital remains unfilled, and one electron goes in its 3d shell, leading to the configuration [Ar] 3d 10 4s 1 ...

Squeezing All Elements in the Periodic Table: Electron Configuration and Electronegativity of the Atoms under Compression. Journal of the American Chemical Society , 2019; 141 (26): 10253 DOI: 10. ...

Three reasons why the periodic table ... group 1 elements have one electron in their outer shell and ... Some chemists maintain that the decision should come down to electron configuration, ...

A little-known genius figured out where all the elements in the periodic table ... not so much using spectra to figure out electron configurations, ... (s=0, p=1, d= 2, and so on). Shell ...

This video excerpt from NOVA's "Hunting the Elements" explains why some elements are more reactive than others.