Using Punnett Squares To Facilitate Students' Understanding of Isotopic Distributions in Mass Spectrometry

摘要

Francis William Aston's discovery of isotopes in 1912 complicated the understanding of the relationship between nuclear physics and chemistry.Dalton's theory of the atom claimed that all atoms of a particular element were identical (1).For most elements,this is not true;there are species of the same element,with different masses,called isotopes.With the 1919 invention by Aston of the mass spectrometer,it is possible to weigh individual nuclei,thereby distinguishing element from element,and isotope from isotope.Using a mass spectrometer themselves,undergraduate students can experimentally weigh atoms as a part of their training and dispel the impression that atoms are somehow "unreal".