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.
