An Introduction to the Electronic Structure of Atoms and Molecules

Dr. Richard F.W. Bader
Professor of Chemistry / McMaster University / Hamilton, Ontario

1.  The Nature of the Problem
2.  The New Physics
3.  The Hydrogen Atom
4.  Many-Electron Atoms
5. Electronic Basis for the Properties of the Elements
  Horizontal Variations
  Vertical Relationships
  Some Chemical Implications
6.  The Chemical Bond
7.  Ionic and Covalent Binding
8.  Molecular Orbitals
Table of Contour Values

1. Estimate the wavelength of the photon which is emitted when a 3p electron falls to a vacancy in the 1s orbital in a chlorine ion. The energies of the 1s and 3p orbitals in chlorine are -2.854 ´ 103 ev and -13.77 ev respectively.
2. In his investigation of the X-ray spectra of the elements, Moseley found that the frequencies of the lines of shortest wavelength could be expressed as a function of the atomic number Z as
where a and s are constants. Account for the general form of the relationship. What is the significance of the factor s?
3. (a) On the basis of your knowledge of the electronic structure of the elements arrange the following substances in the order of their increasing ability to act as oxidizing agents. 
He+, Cl, P, Na, F-
(b) Arrange the following substances in the order of their increasing ability to act as reducing agents. 
Cs, Li, C, S, Cl
4. Rationalize the following observations on the basis of the electronic structures of the halogen atoms and their ions. Iodide ions can be oxidized to elemental iodine by molecular oxygen 
 4HI + O2 ® 2Li + 2H20
but the corresponding reaction does not occur with HCl 
HCl + O2 ® no reaction
5. Account for the fact that the second ionization potential for oxygen is greater than that for fluorine. (I2 for 0 is 35.15 ev and I2 for F is 34.98 ev.) 
6. Which atom or ion in the following pairs has the highest ionization potential? 
(a) N, P 
(b) Mg, Sr 
(c) Ge, As 
(d) Ar, K+
7. Of the following substances: F2, F-, I2, I-
(a) Which is the best oxidizing agent?
(b) Which is the best reducing agent?
(c) Write one chemical equation for a reaction which will illustrate your answers to parts (a) and (b).