Intra-atomic Charge

Isotope research before Isotopy: George Hevesy's early radioactivity research in the Hungarian context

“…This is the starting point of the practical usage of isotopes before isotopy had even been defined and coined 42 . The term «isotopes» appeared for the first time in December 1913, in a letter Soddy sent to Nature 43 .…”

The Chemical Causes of Color

“…Then in 1914, Moseley's work demonstrated that it was the atomic number [11], eventually associated with the number of protons present in an atom, that differentiated atoms from one another rather than the atomic weight. In 1913, Frederick Soddy realized the existence of isotopes [12]; the final piece of the atomic structure puzzle fell into place in 1932 with James Chadwick's discovery of the neutron [13]-so now isotopes could make sense! The finely woven threads of the tapestry describing atomic structure were eventually tied together by an evolving understanding of the nature of X-rays, radioactivity, and the ''rays'' emitted by radioactive elements.…”

On books and chemical elements

“…He named the species of the same element with different atomic weight isotopes, after two Greek words that indicate that they occupy the same place in the periodic table (Soddy 1913). These two concepts may have been immediately accepted, because little later we can find the periodic table ordered according to the atomic numbers in Hildebrand's textbook (Hildebrand 1918).…”