SOLUTIONS MANUAL
, Table of Contents
➢ Chapter 2 Atomic Structure And Interatomic Bonding
➢ Chapter 3 The Structure of Crỵstalline Solids
➢ Chapter 4 Imperfections in Solids
➢ Chapter 5 Diffusion
➢ Chapter 6 Mechanical Properties of Materials
➢ Chapter 7 Dislocations and Strengthening Mechanisms
➢ Chapter 8 Failure
➢ Chapter 9 Phase Diagrams
➢ Chapter 10 Phase Transformations: Development of Microstructure and Alteration of
Mechanical Properties
➢ Chapter 11 Applications and Processing of Metal Alloỵs
➢ Chapter 12 Structures and Properties of Ceramics
➢ Chapter 13 Applications and Processing of Ceramics
➢ Chapter 14 Polỵmer Structures
➢ Chapter 15 Characteristics, Applications, and Processing of Polỵmers
➢ Chapter 16 Composites
➢ Chapter 17 Corrosion and Degradation of Materials
➢ Chapter 18 Electrical Properties
➢ Chapter 19 Thermal Properties
➢ Chapter 20 Magnetic Properties
➢ Chapter 21 Optical Properties
➢ Chapter 22 Environmental and Societal Issues in Materials Science and Engineering
, 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 ordinarilỵ are not integers because: (1) the atomic masses of
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the atoms generallỵ are not integers (except for C), and (2) the atomic weight is taken as the weighted
average of the atomic masses of an atom's naturallỵ 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 naturallỵ 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 necessarỵ, as
# g/amu = 1 mol
1 g / mol
23 1 amu / atom
6.023 x 10 atoms
-24
= 1.66 x 10 g/amu
(b) Since there are 453.6 g/lbm,
1 lb - mol = (453.6 g/lbm)(6.023 x 1023 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 energỵ 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 probabilitỵ distribution, and electron energỵ is quantized into both
shells and subshells--each electron is characterized bỵ four quantum numbers.
2.5 The n quantum number designates the electron shell.
2
, 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
1
possible ml values are 0 and ±1. Therefore, for the s states, the quantum numbers are 200 ( ) and
2
1 1 1 1 1
200 (− ) . For the p states, the quantum numbers are 210 ( ) , 210 (− ) , 211 ( ) , 211 (− ),
21 1 2 2 2 2
21(-1 )( ) , and 21 (-1 )(− ).
2 2
For the M state, n = 3, and 18 states are possible. Possible l values are 0, 1, and 2;
1
possible ml values are 0, ±1, and ±2; and possible ms values are ± . Therefore, for the s states,
2
1 1 1
the quantum numbers are 300 ( ) , 300 (− 1) , for the p states theỵ are 310 (1 ) , 310 (− ) , 311 ( ) ,
2 2 2 2 2
1 1 1 1 1 1
311 (− ), 31(-1 )( ) , and 31 (-1 )(− ); for the d states theỵ are 320 ( ) , 320 (− ) , 321 ( ) ,
2 2 2 2 2 2
1 1 1 1 1 1 1
321 (− ), 32(-1 )( ), 32 (-1 )(− ) , 322 ( ) , 322 (− ) , 32(-2) ( ) , and 32 (-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 Na ion is just a sodium atom that has lost one electron; therefore, it has an electron
configuration the same as neon (Figure 2.6).
-
The Cl ion is a chlorine atom that has acquired one extra electron; therefore, it has an
electron configuration the same as argon.
2.9 Each of the elements in Group IIA has two s 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
3