APPENDIX 2 ANSWERS TO IN-TEXT PROBLEMS Problems are of two types: in-text problems that appear within the body of each chapter, and end of-chapter problems. This appendix gives brief answers to all the in-text problems. More detailed discussions of in-text problems as well as detailed solutions to all the end-of-chapter problems are provided in a separate Study Guide and Student Solutions Manual. Answers to part(a) of those in-text problems with multiple parts have been provided in the form of a sample solution within ach chapter and are not repeated here. CHAPTER 1 1.2 All the third-row elements have a neon core containing 10 electrons(1s22s2p6).The ele ments in the third row, their atomic numbers Z, and their electron configurations beyond the neon core are nad(Z=113s;Mg(Z=12)32;A(Z=13)323p1;S(z=14)323p3py;P(=15) 3233p23p2;S(z=16)3s23p2323p2;Cl(z=17)3s23p23p23p2;Ar(z=18) 323p23p232 1.3 Those ions that possess a noble gas electron configuration are(a)K;(c)H;(e)F; and 1.4 Electron configuration of C+ is 1522322p'; electron configuration of C- is 1322322p.Nei rC nor C possesses a noble gas electron configuration 1.5H:F HH 1.6H:C:C:H HH H H 1.8 Carbon bears a partial positive charge in CH3 Cl. It is partially negative in both CH4 and CH3Li, but the degree of negative charge is greater in CH3Li 1.9 (b) Sulfur has a formal charge of +2 in the lewis struct sulfuric acid. the two oxygens bonded only to sulfur each have a formal charge of -l, and the oxygens and hydrogens of the two OH groups have no formal charge;(c)none of the atoms have a formal charge in the Lewis structure given for nitrous acid 1.10 The electron counts of nitrogen in ammonium ion and boron in borohydride ion are both 4 Chalf of 8 electrons in covalent bonds). Since a neutral nitrogen has 5 electrons in its valence shell an electron count of 4 gives it a formal charge of +1. a neutral boron has 3 valence electrons, so lat an electron count of 4 in borohydride ion corresponds to a formal charge of -1 A-9 Forward Main Menu TOC Study Guide Toc Student OLCMHHE WebsiteAPPENDIX 2 ANSWERS TO IN-TEXT PROBLEMS A-9 Problems are of two types: in-text problems that appear within the body of each chapter, and end￾of-chapter problems. This appendix gives brief answers to all the in-text problems. More detailed discussions of in-text problems as well as detailed solutions to all the end-of-chapter problems are provided in a separate Study Guide and Student Solutions Manual. Answers to part (a) of those in-text problems with multiple parts have been provided in the form of a sample solution within each chapter and are not repeated here. CHAPTER 1 1.1 4 1.2 All the third-row elements have a neon core containing 10 electrons (1s 2 2s 2 2p6 ). The ele￾ments in the third row, their atomic numbers Z, and their electron configurations beyond the neon core are Na(Z 11)3s 1 ; Mg(Z 12)3s 2 ; Al(Z 13) 3s 2 3px 1 ; Si(Z 14) 3s 2 3px 1 3py 1 ; P (Z 15) 3s 2 3px 1 3py 1 3pz 1 ; S (Z 16) 3s 2 3px 2 3py 1 3pz 1 ; Cl (Z 17) 3s 2 3px 2 3py 2 3pz 1 ; Ar (Z 18) 3s 2 3px 2 3py 2 3pz 2 . 1.3 Those ions that possess a noble gas electron configuration are (a) K; (c) H; (e) F; and (f) Ca2. 1.4 Electron configuration of C is 1s 2 2s 2 2p1 ; electron configuration of C is 1s 2 2s 2 2p3 . Nei￾ther C nor C possesses a noble gas electron configuration. 1.5 1.6 1.7 (b) (c) 1.8 Carbon bears a partial positive charge in CH3Cl. It is partially negative in both CH4 and CH3Li, but the degree of negative charge is greater in CH3Li. 1.9 (b) Sulfur has a formal charge of 2 in the Lewis structure given for sulfuric acid, the two oxygens bonded only to sulfur each have a formal charge of 1, and the oxygens and hydrogens of the two OH groups have no formal charge; (c) none of the atoms have a formal charge in the Lewis structure given for nitrous acid. 1.10 The electron counts of nitrogen in ammonium ion and boron in borohydride ion are both 4 (half of 8 electrons in covalent bonds). Since a neutral nitrogen has 5 electrons in its valence shell, an electron count of 4 gives it a formal charge of 1. A neutral boron has 3 valence electrons, so that an electron count of 4 in borohydride ion corresponds to a formal charge of 1. H C H H C C N F F C C F F H C H H H H H C H F