This chapter, Periodic Classification of Elements, includes exercises that talks about three different periodic tables. We first are informed about classification of elements in terms of their properties in the beginning. It then moves on to explain to students exactly what the Dobereiner's triad is and the concept behind it.
Students also learn about the Newland's Law of Octaves that later was removed and Mendeleev's periodic table was introduced. This chapter finally proceeds to explain the modern periodic table and the classification of the elements present on it.