Solution Manual for Materials Science and Engineering: An Introduction (9th Edition) by Callister – Complete Answers for Chapters 2 to 22

Solution Manual for Materials Science and Engineering: An Introduction (9th Edition) by
Callister – Complete Answers for Chapters 2 to 22

,Solution Manual for Materials Science and Engineering: An Introduction (9th Edition) by
Callister – Complete Answers for Chapters 2 to 22

,Solution Manual for Materials Science and Engineering: An Introduction (9th Edition) by
Callister – Complete Answers for Chapters 2 to 22



CHAPTER 2


ATOMIC STRUCTURE AND INTERATOMIC BONDING


PROBLEM SOLUTIONS


2.1 (a) When two or more atoms of an element have different atomic masses, each is termed an
isotope.
(b)
The atomic weights of the elements ordinarily are not integers because: (1) the atomic
12 C), and (2) the atomic weight is
masses of the atoms generally are not integers (except for
taken as the weighted average of the atomic masses of an atom's naturally occurring isotopes.


2.2 Atomic mass is the mass of an individual atom, whereas atomic weight is the average
(weighted) of the atomic masses of an atom's naturally occurring isotopes.


2.3 (a) In order to determine the number of grams in one amu of material, appropriate manipulation
of the amu/atom, g/mol, and atom/mol relationships is all that is necessary, as

 
#g/amu =
1 mol
( 1 g/mol
6.023 x 1023 atoms 1 amu/atom
)
-24
= 1.66 x 10 g/amu


(b) Since there are 453.6 g/lbm,


23
1 lb-mol = (453.6 g/lbm)(6.023 x 10 atoms/g-mol)


26
= 2.73 x 10 atoms/lb-mol


2.4 (a) Two important quantum-mechanical concepts associated with the Bohr model of the atom
are that electrons are particles moving in discrete orbitals, and electron energy is quantized into
shells.
(b) Two important refinements resulting from the wave-mechanical atomic model are that
electron position is described in terms of a probability distribution, and electron energy is
quantized into both shells and subshells--each electron is characterized by four quantum
numbers.



1

, Solution Manual for Materials Science and Engineering: An Introduction (9th Edition) by
Callister – Complete Answers for Chapters 2 to 22




2.5 The n quantum number designates the electron shell.
The l quantum number designates the electron subshell.
The m quantum number designates the number of electron states in each electron subshell.
l
The m quantum number designates the spin moment on each electron.
s


2.6 For the L state, n = 2, and eight electron states are possible. Possible l values are 0 and 1,
while possible ml values are 0 and 1. Therefore, for the s states, the quantum numbers are
200( 1) and 200(- 1). For the p states, the quantum numbers are 210( 1), 210(- 1), 211( 1), 211(-
2 2 2 2 2
1 1 1
), 21(-1)( ), and 21(-1)(- ).
2 2 2
For the M state, n = 3, and 18 states are possible. Possible l values are 0, 1, and 2;
1
possible m l values are 0, 1, and 2; and possible m s values are  . Therefore, for the s
2
1 1 1 1
states, the quantum numbers are 300( ), 300(- ), for the p states they are 310( ), 310(- ),
2 2 2 2
311(\F(1,2)), 311(-\F(1,2)), 31(-1)(\F(1,2)), and 31(-1)(-\F(1,2)); for the d states they are
1 1
320( 1), 320(- 1), 321( 1), 321(- 1), 32(-1)( ), 32(-1)(- 1), 322( 1), 322(- 1), 32(-2)( ), and 32(-2)(- 1).
2 2 2 2 2 2 2 2 2 2


2.7 The electron configurations of the ions are determined using Table 2.2.

2+ 2 2 6 2 6 6
Fe - 1s 2s 2p 3s 3p 3d
3+ 2 2 6 2 6 5
Fe - 1s 2s 2p 3s 3p 3d
+ 2 2 6 2 6 10
Cu - 1s 2s 2p 3s 3p 3d
2+ 2 2 6 2 6 10 2 6 10 2 6
Ba - 1s 2s 2p 3s 3p 3d 4s 4p 4d 5s 5p
- 2 2 6 2 6 10 2 6
Br - 1s 2s 2p 3s 3p 3d 4s 4p
2- 2 2 6 2 6
S - 1s 2s 2p 3s 3p


+
2.8 The Cs ion is just a cesium atom that has lost one electron; therefore, it has an electron
configuration the same as xenon (Figure 2.6).
-
The Br ion is a bromine atom that has acquired one extra electron; therefore, it has an
electron configuration the same as krypton.


2.9 Each of the elements in Group VIIA has five p electrons.


2 2 6 2 6 7 2
2.10 (a) The 1s 2s 2p 3s 3p 3d 4s electron configuration is that of a transition metal because
of an incomplete d subshell.




2