isotope: [20] The term isotope for a version of an element with a particular atomic weight was coined in 1913 by the British chemist Frederick Soddy. It means literally ‘equal place’ and was formed from two Greek components, the prefix iso- ‘equal’ and the noun tópos ‘place’ (source of English topic). The reason for the coinage was that although isotopes of the same element have different atomic weights, they occupy the ‘same place’ in the periodic table of elements. => topic
1913, literally "having the same place," introduced by British chemist Frederick Soddy (1877-1956) on suggestion of Margaret Todd, from Greek isos "equal" (see iso-) + topos "place" (see topos); so called because despite the different atomic weights, the various forms of an element occupy the same place on the periodic table.
