Callister

SOLUTIONS TO PROBLEMS PREFACE

This section of instructor's resource materials contains solutions and answers to all problems and questions that appear in the textbook. My penmanship leaves something to be desired; therefore, I generated these solutions/answers using computer software so that the resulting product would be "readable." Furthermore, I endeavored to provide complete and detailedsolutions in order that: (1) the instructor, without having to take time to solve a problem, will understand what principles/skills are to be learned by its solution; and (2) to facilitate student understanding/learning when the solution is posted. I would recommend that the course instructor consult these solutions/answers before assigning problems and questions. In doing so, he or she ensuresthat the students will be drilled in the intended principles and concepts. In addition, the instructor may provide appropriate hints for some of the more difficult problems. With regard to symbols, in the text material I elected to boldface those symbols that are italicized in the textbook. Furthermore, I also endeavored to be consistent relative to symbol style. However, in several instances,symbols that appear in the textbook were not available, and it was necessary to make appropriate substitutions. These include the following: the letter a (unit cell edge length, crack length) is used in place of the cursive a. And Roman E and F replace script E (electric field in Chapter 18) and script F (Faraday's constant in Chapter 17), respectively. I have exercised extreme care in designing theseproblems/questions, and then in solving them. However, no matter how careful one is with the preparation of a work such as this, errors will always remain in the final product. Therefore, corrections, suggestions, and comments from instructors who use the textbook (as well as their teaching assistants) pertaining to homework problems/solutions are welcomed. These may be sent to me in care of thepublisher.

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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 masses of the atoms generally are not integers (except for
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C), and (2) the atomic weight is taken as theweighted 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/molrelationships is all that is necessary, as
⎛ ⎞ ⎛ 1 g / mol ⎞ 1 mol # g/amu = ⎜ ⎜ ⎟ 23 atoms ⎟ ⎝ 1 amu / atom ⎠ ⎝ 6.023 x 10 ⎠

= 1.66 x 10-24 g/amu (b) Since there are 453.6 g/lbm,
1 lb - mol = 453.6 g/lbm 6.023 x 10

(

)(

23

atoms/g - mol

)

= 2.73 x 1026 atoms/lb-mol

2.4 (a) Two important quantum-mechanical concepts associated with the Bohr model of the atom are that electrons areparticles 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.

2.5 The n quantum numberdesignates the electron shell.

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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,...