A CHEMISTRY 200 RESOURCE

Silberberg's CHAPTER 8 

Electron Configuration and Chemical Periodicity (pp 287-323)

WHY IS THIS CHAPTER IMPORTANT?

From Silberberg (p 288): "The goal of this chapter is to show how the periodic table, condensed from countless hours of laboratory work by 19th century chemists, is perfectly consistent with the atomic model developed by 20th century physicists. [This chapter] takes up where we left off in Chapter 7...extending the quantum-mechanical model [which applied to the hydrogen atom only] to many-electron atoms..."

 Chapter 8 Outline

8.1 Characteristics of Many-Electron Atoms

8.2 The Quantum-Mechanical Atom and the Periodic Table

8.3 Trends in Some Key Periodic Atomic Properties

8.4 The Connection Between Atomic Structure and Chemical Reactivity

 

Breakdown, Discussion & Help With Sample Problems: What You Should Know

8.1 Characteristics of Many-Electron Atoms

There are four quantum numbers of electrons in atoms. Three of these (principal quantum number, the azimuthal quantum number, and the magnetic quantum number) were discussed in Section 7.4. The fourth quantum number is the spin quantum number...which indicates the direction of electron spin.

With all four quantum numbers in hand, CHEM 200 students can therefore tackle the Pauli exclusion principle, which states that no two electrons in the same atom can have the same set of four quantum numbers.

Page 292 in Silberberg's text includes a list of four consequences of electrostatic interactions between electrons...these consequences are important details in the arsenal of a well-informed CHEM 200 student.

8.2 The Quantum-Mechanical Atom and the Periodic Table

The material presented in Chapter 7, along with that found in Section 8.1, culminates in 8.2.

In this section, Silberberg describes the aufbau principle...a technique used to build up the atoms in the periodic chart...one-by-one...by adding one electron at a time (starting with hydrogen).

Tables 8.3 and 8.4 include the partial orbital diagrams and electronic configurations for the elements in Period 3 and Period 4, respectively.

click here for a few words about SAMPLE PROBLEM 8.2 (page 302-3)

8.3 Trends in Some Key Periodic Atomic Properties

From Silberberg (p 303): "All physical and chemical behavior of the elements is based ultimately on the electron configurations of their atoms."

Section 8.2 gave CHEM 200 students the ability to determine the electron configurations for most of the atoms on the periodic chart...and 8.3 puts a face on the dryness of ther periodic chart by focusing on three properties of atoms that are influenced directly by the electron configuration: atomic size, ionization energy, and electron affinity.

All three of these properties are periodic in that they generally increase and decresase in recurring (and predictable) manners throughout the periodic table.

click here for a few words about SAMPLE PROBLEM 8.3 (page 306)

click here for a few words about SAMPLE PROBLEM 8.4 (page 309)

8.4 The Connection Between Atomic Structure and Chemical Reactivity

The material presented in section 8.4 is the next step in utilizing the information presented in Section 8.2. Specifically, trends in metallic behavior (p 312), properties of monatomic ions (p 314), paramagnetism and diamagnetism (p 316), and ionic size vs. atomic size (p 317) can all be rationized with the knowledge that CHEM 200 students have gained from Chapters 7 and 8.

Of particular importance are the concepts of paramagnetism and diamagnetism (Sample Problem 8.7).

click here for a few words about SAMPLE PROBLEM 8.7 (page 317)

Chapter 8 additional suggestions: 5 essential problems--

exercises such as numbers 8.20, 8.26, 8.28, 8.40, and 8.63 are all straightforward problems of the type that are often found on CHEM 200 exams

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