Descriptive Inorganic Chemistry, DIC, Fifth edition, 5 edition
Chapter 1 even answers:

1 
Chapter 1 
 
THE ELECTRONIC STRUCTURE OF THE ATOM: A REVIEW 
 
Exercises 
1.2  (a) Region in space around a nucleus where the probability of finding an 
electron is high. 
(b) Orbital energy levels of the same energy. 
(c) When occupying orbitals of equal energy, it is energetically preferable 
for the electrons to adopt a parallel spin arrangement. 
 
1.4  5. 
 
1.6  6s. 
 
1.8  The quantum number l relates to the orbital shape. 
 
1.10  The pairing energy for the double occupancy of the 2s orbital is less than 
the energy separation of the 2s and 2p orbitals. 
 
1.12  (a) [Ar]4s2; (b) [Ar]4s13d5; (c) [Xe]6s24f145d106p2. 
 
1.14  (a) [Ar]; (b) [Ar]3d7; (c) [Ar]3d3. 
 
1.16  2+ and 4+.  Tin has a noble gas core ground-state electron configuration of 
[Kr]5s24d105p2.  The two 5p electrons are lost first, giving an ion of 2+ 
charge; the two 5s electrons are lost next, giving an ion of 4+ charge. 
 
1.18  4+.  Zirconium has a noble gas core ground-state electron configuration of 
[Ar]4s23d2.  Thus loss of both the two 4s electrons and the two 3d 
electrons will give a 4+ ion. 
 
2     Chapter 1  
1.20  (a) 3; (b) 2; (c) 4. 
 
 
1.22  (a) and (d). 
 
Beyond the Basics 
 
1.24  The Dirac wave equation was developed by the English physicist P. A. M. 
Dirac.  He applied the ideas of Einstein’s special theory of relativity to 
quantum mechanics.  Dirac’s model requires four quantum numbers, not 
the three of the Schrödinger model (where the spin quantum number is not 
part of the solution to the equation).  A fourth quantum number results 
from the special theory of relativity where events are defined by the three 
spatial coordinates plus a time coordinate. 
In the Dirac model, like the Schrödinger model, the principal 
quantum number, n, determines the size of an orbital.  The other quantum 
numbers have different meanings—the third and the fourth (instead of the 
second) determine the shape of the orbitals.  The shapes of the orbitals 
themselves differ from those using the Schrödinger equation, and there are 
no nodes.  This removes the conceptual problem of how an electron moves 
from one lobe of a p orbital to the other if there is a zero probability in 
between.  The answer is that the ―simplistic‖ Schrödinger equation is in 
error.  For high-atomic-number atoms, relativistic effects become of 
increasing importance and the Schrödinger equation becomes inadequate; 
the Dirac equation must be used. 
For a good introduction to the Dirac equation, see R. E. Powell, 
Relativistic Quantum Chemistry, J. Chem. Educ. 45 (1968): 558–563. 
 
1.26  Curium. [Rn]7s
2
5f
7
6d
1
. 
 
1.28  Of course, one can argue that orbitals are human constructs only! This 
question is a good topic for debate, but these authors veers toward the 
view that an orbital actually exists only when it is populated. Empty 
orbitals only potentially exist.