CHAPTER 1 Structure and Properties of Organic Compounds 3 TABLE 1.1 Covalences of H and Second-Period Elements in Groups 2 through 7 Group 1 2 4 5 6 1 Lewis Symbol H .Be B F Covalence 1 2 3 4 3 2 1 H-B-H H H-N-H HH HReH H H-F. Hydrogen Beryllium Boron H HH Hydrogen hydride hydride* Methane Ammonia Water fluoride Exists as B.He TABLE 1.2 Normal Covalent Bonding BONDING FOR C BONDING FOR N BONDING FOR O =C= -C≡ -N- -N= -0- 0= as in as in as in as in as H -H :0=C=0:H-C=C-H H-N-H H-0-N=0::N=C-H H-0-H 0= H H Methane Ethene Ammonia Nitrous Water Formaldehyde (Ethylene) dioxide (Acetylene) acid cyanide Problem 1.4 Write str ural and condensed formulas for (a)three isomers with molecular formula CHand (b)two isomers with molecular formulaC.H (a)Carbon forms four covalent bonds:hydrogen forms one.The carbons can bond to each other in a chain: -H (structural formula) CH:(CH2)CHs (condensed formula) n-Pentane or there can be"branches"(shown circled in Fig.1.3)on the linear backbone (shown in a rectangle) (b)We can have a double bond or a ring H H CHC-CH2 H Propene(Propylene) CyclopropaneProblem 1.4 Write structural and condensed formulas for (a) three isomers with molecular formula C5 H12 and (b) two isomers with molecular formula C3H6. (a) Carbon forms four covalent bonds; hydrogen forms one. The carbons can bond to each other in a chain: CHAPTER 1 Structure and Properties of Organic Compounds 3 Group Lewis Symbol Covalence Compounds with H 1 H. 1 2 Be.. 2 3 B. . . 3 * Exists as B2 H6 . 45 67 C. . . . N. . . . . O. . . . . . F: . . . . . 43 21 H—H Hydrogen H—Be—H Beryllium hydride H—B—H | Boron hydride* H | H—C—H | H Methane . . H—N—H | H Ammonia . . H—O—H . . Water . . H—F: . . Hydrogen fluoride H BONDING FOR C as in as in as in as in as in as in as in as in as in BONDING FOR N BONDING FOR O C C C C H H C H H . . . . C C O O C H H H H C H H Methane Ethene (Ethylene) Carbon dioxide Ethyne (Acetylene) Ammonia Nitrous acid Hydrogen cyanide Water Formaldehyde . . . . . . H . . O O: N . . HOH . . . . :N C H . . O . . H N H H H H C C . . N . . . . O . . . . O . . N . . N : : or there can be “branches” (shown circled in Fig. 1.3) on the linear backbone (shown in a rectangle). (b) We can have a double bond or a ring. TABLE 1.1 Covalences of H and Second-Period Elements in Groups 2 through 7 TABLE 1.2 Normal Covalent Bonding