Icon of Chemistry: The Periodic System of Chemical Elements in the New Century

摘要

Every science has its basic concepts and principles, and for teaching in schools and universities, they must be expressed distinctly. In research and development, ambiguous definitions may serve as inspiration, although this approach is at variance with the "logician's program" for science. Particularly in chemistry, fuzzy concepts such as aromaticity, conjugation, electrophilici-ty, polarity, and so forth are very practical. Another example is the concept of a Periodic System of Elements (PSE), which is graphically rendered iconic by many different periodic tables.