<P> In 1914 , a year before he was killed in action at Gallipoli , the English physicist Henry Moseley found a relationship between the X-ray wavelength of an element and its atomic number . He was then able to re-sequence the periodic table by nuclear charge , rather than by atomic weight . Before this discovery , atomic numbers were sequential numbers based on an element 's atomic weight . Moseley 's discovery showed that atomic numbers were in fact based upon experimental measurements . </P>
<P> In 1914 , a year before he was killed in action at Gallipoli , the English physicist Henry Moseley found a relationship between the X-ray wavelength of an element and its atomic number . He was then able to re-sequence the periodic table by nuclear charge , rather than by atomic weight . Before this discovery , atomic numbers were sequential numbers based on an element 's atomic weight . Moseley 's discovery showed that atomic numbers were in fact based upon experimental measurements . </P>
who changed the periodic table to atomic number
who changed the periodic table to atomic number
Henry Moseley
Henry Moseley