Francium electronic structure

During World War II, more work was done on the elements, particularly as part of the Manhattan Project. After the war, the existence of these new elements was made public. All of the naturally occurring elements from hydrogen to uranium, including the small number of artificially created but low-number elements francium, astatine, and promethium, had been found and put into the periodic table. Combined with the work of Rutherford and Bohr, this work made the physical structure of the atom clear and proved beyond all doubt. Even if physics would start to find smaller parts within the electron, the neutron, and the proton, from a chemical point of view, the atom was complete. Atoms and molecules had been shown to be real, they way they combined was... 

The first hfs measurements in francium were made with the ABMR method, giving nuclear spin values for the sequence of isotopes - 5.22o-222pj. 2], These experiments were followed by atomic-beam laser experiments [23] which, after the identification of the Dj qitical line, gave results on the hypeifine structure constants in the 7s ground state and the 7p excited state as well as isotope shifts in 208-2i3Fr. Fuller measurements in francium include the nuclear spin of Fr, the nuclear g-factor of Fr and the electronic g-factor of francium by the ABMR method [13], the identification of the D, optical transition by atomic-beam laser spectroscopy [24], and the 7s —> 8p and 7s -> 8p Pj transitions... 

Thus, the structures of the elements above radon (element 86) through uranium were written to show the addition of the next two electrons in the 7s shell for element 87 (francium) and element 88 (radium) and addition in the 6d shell for actinium, thorium, protactinium and uranium (Latimer and Hildebrand 1940 Richtmeyer and Kennard 1942 Taylor and Glasstone 1942). 

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