1559r_-h0101-1710/22/051:48Page9 8.chapter 1 STRUCTURE AND BONDNG IN ORGANIC MOLECULES H >C6-H一 H (e)H- H-6 B-CO H-6 H-0 2.a6cN一6：C H:H一 Equivalent,major Not as good (oxygen sextet) o是是一是墨 060:一00：0：d:6: Major Major N: H Major(b) (e) 27. (a) In some of these answers, additional, less favorable forms are shown for comparison purposes. (b) (c) (d) (e) Identical. (f) (g) H H H H C N O
(Positive oxygen) (Carbon sextet) Major H H H H C N
O H H H H C N
O O Cl O O Cl O
O Cl O Major Major H H H H H C C C H H H H H C C C Equivalent, major Not as good (oxygen sextet) O O O
O O O
O O O
O O O
C O H N H H Major (no separation of charge) C O H N H H H C N H
O H
H C N H H H C Major (negative charge prefers the more electronegative atom—nitrogen) H C N H H H C O C N N O C Major (negative charge prefers the more electronegative atom—oxygen) H O O H O B H O H O B (Minor contributor: boron lacks an octet) Move electrons away from the negatively charged atom O C H H H
C O O H H H
(Minor contributor: carbon lacks an octet) Move electrons toward the positively charged atom 8 • Chapter 1 STRUCTURE AND BONDING IN ORGANIC MOLECULES 1559T_ch01_01-17 10/22/05 1:48 Page 8