"Chemical elements." . . "Periodic table." . . "Physical chemistry." . . "Periodic law." . . . . . . . . "Shows the different physical and chemical properties of the elements and the patterns of these properties in the periodic table."@en . . . . "Chemistry: the periodic table and periodicity" . . "Stresses the analysis of data to discover relationships and to use them to develop an organized body of knowledge that can be used to make prediction." . "Discusses the properties of chemical elements and their patterns as expressed in the periodic table. Topics include: relationship between the electron structure of the atom and its properties, families of elements, valence, atomic number." . "The periodic table and periodicity" . "The periodic table and periodicity"@en . . . . "The Periodic table and periodicity"@en . "The Periodic table and periodicity" . . "Animation helps to explain the Periodic Table, a way of organizing physical and chemical properties of the elements." . "Animation helps to develop the relationship between the electronic structure of an atom and its properties, demonstrating clearly why there are families of elements and gradual changes in the properties of elements arranged by atomic number across the table."@en . . . . . . . . . . . . . . . "This program expalins the development and structure of the Periodic Table of Elements, a basic tool for understanding chemistry." . . . . . .