In this chapter, we explore the relationship between the electron configurations of the elements, as reflected in their arrangement in the periodic table, and their physical and chemical properties. Created by Sir William Crookes (1832–1919), the spiral represents the relationships between the elements and the order of evolution of the elements from what he believed to be primal matter.

Chapter 6 'The Structure of Atoms' ended with the observation that, because all the elements in a column have the same valence electron configuration, the periodic table can be used to find the electron configuration of most of the elements at a glance.Ĭrookes’s Spiral Periodic Table, 1888. Thus because of their periodic similarities in electron configuration, atoms in the same column of the periodic table tend to form compounds with the same oxidation states and stoichiometries. In contrast, the alkali metals have a single valence electron outside a closed shell and readily lose this electron to elements that require electrons to achieve an octet, such as the halogens. Because of their filled valence shells, the noble gases are generally unreactive. These closed shells are actually filled s and p subshells with a total of eight electrons, which are called octets helium is an exception, with a closed 1 s shell that has only two electrons. For example, the noble gases have what is often called filled or closed-shell valence electron configurations. In using this model to describe the electronic structures of the elements in order of increasing atomic number, we saw that periodic similarities in electron configuration correlate with periodic similarities in properties, which is the basis for the structure of the periodic table. In Chapter 6 'The Structure of Atoms', we presented the contemporary quantum mechanical model of the atom. Chapter 7 The Periodic Table and Periodic Trends

Trends in reactivity periodic table