#Chem 161-2007 Exam III + answers

#Chem 161-2007 Exam III + answers - 1. Rank the following...

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1. Rank the following species according to increasing 1st ionization energy. (Lowest first, Highest last) F, S, Ne, K, P A. K < S < P < Ne < F B. Ne < S < K < P < F C . K < S < P < F < Ne D. F < Ne < P < S < K E. K < F < P < S < Ne According to the periodic table, the atom with the lowest ionization energy is in the lower left-hand corner, and the atom with the highest ionization energy is in the upper right- hand corner. Therefore, K < P < S < F < Ne 19 K = 1s 2 2s 2 2p 6 3s 2 3p 6 4s 1 15 P = 1s 2 2s 2 2p 6 3s 2 3p 3 16 S = 1s 2 2s 2 2p 6 3s 2 3p 4 19+ 1+ 15+ 16+ 5+ 6+ 9 F = 1s 2 2s 2 2p 5 10 Ne = 1s 2 2s 2 2p 6 9+ 7+ 10+ 8+ According to the above schematics, the order should also be K < P < S < F < Ne. But this order is not an option. The closest option is K < S < P < F < Ne. Is this valid? Let’s look at the subshell differences of the nearest neighbors, S and P. S removes an electron from 3p4, which is easy to do since it would provide a half-filled subshell. P removes an electron with more difficultly, because it would lose the stability of a half-filled p 2e - 8e - 2e - 7e - 2e - 6e - 8e - 2e - 5e - 8e - 2e - 1e - 8e - 8e - X X X X X X X X X X X X X X
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subshell. Hence, despite the effective nuclear charge (which indicates that it is easier to remove an electron from phosphorous), the subshell influence suggests that it is easier to remove an electron from sulfur. Therefore, K < S < P < F < Ne is consistent with the general rules combined with the subshell influence. 2. Which of the following bonds has the most ionic character? A. N - O B. Na - I C. O - F D. Cl - Cl E . Rb - F The substance with the most ionic character would be the one with the largest difference in electronegativity between the two atoms, i.e., the largest dipole. The most electronegative atom is in the upper right-hand corner, and the least electronegative atom is in the lower left-hand corner. In addition, ionic character refers to an ionic substance, which is a combination of a metal cation and an anion. A. N and O are near each other in the periodic table, both in the upper right-hand corner. Therefore, they should have only a small difference in electronegativity. B. Na and I are far from each other in the periodic table, I in the lower right-hand corner, and Na in the upper left-hand corner. They should have a large difference in electronegativity, but not as large a difference as a metal in the lower left-hand corner and a halogen in the upper right-hand corner. C. O and F are near each other in the periodic table, both in the upper right-hand corner. Therefore, they should have only a small difference in electronegativity. D. Cl and Cl have the same electronegativity values. Therefore, they should have zero difference in electronegativity. E.
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#Chem 161-2007 Exam III + answers - 1. Rank the following...

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