(ˌpɪərɪˈɒdɪk) n (Chemistry) the classification of the elements based on the periodic lawTranslations EncyclopediaSeeperiodic table
periodic system
per·i·od·ic sys·tem
the arrangement of the chemical elements in a definite order as indicated by their respective atomic numbers in such a way that groups of elements with similar chemical properties (similar valence shell electron number) are grouped together. See: Mendeléeff law.