mar 1, 1913 - Later expansions and the end of the periodic table

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As early as 1913, Bohr's research on electronic structure led physicists such as Johannes Rydberg to look at the properties of undiscovered elements heavier than uranium. Many agreed that the next noble gas after radon would most likely have the atomic number 118, from which it followed that the transition series in the seventh period should resemble those in the sixth.

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