General Chemistry Principles, Patterns, and Applications, 2011

13. A new element is believed to have been discovered by a team of Russian and American scientists, although
its existence is yet to be independently confirmed. Six atoms of element 117, temporarily named
ununseptium, were created by smashing together isotopes of calcium with the element berkelium. Give the
following:
a. the complete electron configuration of this element
b. the valence electron configuration
c. the number of unpaired electrons in the valence shell
Chapter 7
The Periodic Table and Periodic Trends
In , we presented the contemporary quantum mechanical model of the atom. 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. For example, the noble gases have what is often called filled or closed-shell valence electron
configurations. These closed shells are actually filled s and psubshells with a total of eight electrons, which are
called octets; helium is an exception, with a closed 1s shell that has only two electrons. Because of their filled valence
shells, the noble gases are generally unreactive. 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.
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. 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.
Crookes’s Spiral Periodic Table, 1888. 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.
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. In particular, we focus on the
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