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Unformatted text preview: 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 12 C), and (2) the atomic weight is 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 6.023 x 10 23 atoms 1 g / mol 1 amu / atom = 1.66 x 1024 g/amu (b) Since there are 453.6 g/lb m , 1 lb  mol = 453.6 g/lb m ( 29 6.023 x 10 23 atoms/g mol ( 29 = 2.73 x 10 26 atoms/lbmol 2.4 (a) Two important quantummechanical 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 wavemechanical atomic model are that electron position is described in terms of a probability distribution, and electron energy is quantized into both shells and subshellseach electron is characterized by four quantum numbers. 2.5 The n quantum number designates the electron shell. 2 The l quantum number designates the electron subshell. The m l quantum number designates the number of electron states in each electron subshell. The m s quantum number designates the spin moment on each electron. 2.6 For the L state, n = 2, and eight electron states are possible. Possible l values are 0 and 1, while possible m l values are 0 and ±1. Therefore, for the s states, the quantum numbers are 200( 1 2 ) and 200( 1 2 ) . For the p states, the quantum numbers are 210( 1 2 ) , 210( 1 2 ) , 211( 1 2 ) , 211( 1 2 ), 21(1 )( 1 2 ) , and 21(1 )( 1 2 ). For the M state, n = 3, and 18 states are possible. Possible l values are 0, 1, and 2; possible m l values are 0, ±1, and ±2; and possible m s values are ± 1 2 . Therefore, for the s states, the quantum numbers are 300( 1 2 ) , 300( 1 2 ) , for the p states they are 310( 1 2 ) , 310( 1 2 ) , 311( 1 2 ) , 311( 1 2 ), 31(1 )( 1 2 ) , and 31(1 )( 1 2 ); for the d states they are 320( 1 2 ) , 320( 1 2 ) , 321( 1 2 ) , 321( 1 2 ), 32(1 )( 1 2 ), 32(1 )( 1 2 ) , 322 ( 1 2 ) , 322 ( 1...
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 Spring '08
 KIM
 Atom, Electron, RO, 1s 2s

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