AK11 - (M) For each species, we first draw the Lewis...

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Unformatted text preview: (M) For each species, we first draw the Lewis structure, to help explain th bondingf ’ ’M“ (a) In CO2 , there are a total of 4 + (2 x 6) .= 16 valence electrons, or 8 irs. C is the central atom. The Lewis structure is §=C=§ The molecule is linear and is sp hybridized. (b) In HONO2 , there are a total of 1+5 +(3 x 6) = 24 valence electrons or 12 H_6_N._:5 pairs. N is the central atom, and a plausible Lewis structure is show on the ‘ 0, right The molecule is trigonal planar around N which is sz hybrid zed. The O in the H—O—N portion of the molecule is Sp3 hybridized. pairs. Cl is the central atom, and a plausible Lewis structure is sho right. The electron-group geometry around Cl is tetrahedral, indica 'ng that Cl is sp3 hybridized. - V (c) ‘In C10; , there are a total of 7 + (3 x 6) + 1 = 26 valence electrons, o 13 <E__a_:—ql>‘ I (d) In BF; , there are a total of 3 +(4 x 7) + l = 32 valence electrons, or 16 pairs. B m — is the central atom, and a plausible Lewis structure is shown on the 'ght. The E_|B__—fl electron-group geometry is tetrahedral, indicating thatB is Sp3 hyb 'dized. LlF-I _ ’ (E) In NSF there are 5 i 6 +_:7 = 18 valence electrons, or 9 electron pairs. the following Lowis structure, lN=S-—_El there are two atoms bonded to the central S which has a lone pair. Thus, the electron group geometry around the central S is trigonal pl ar (with $192 hybridization) and the molecular shape is bent. (D) (a) 'In N02", there are a total of 5 + (2 x 6) + l = 18 valence electrons, A plausible Lewis structure follows 6a: N — g), The e" group geometry around N is trigonal planar, all bond angles a?ound that atom are 120° , an the hybridization of N is Sp2 . The three bonds in this molecule are: 0': 0,1(2py)1 ——N(sp2)1 0': 0b (2px)I ——N(sz)1 and 7:: 03(21), (b) In I3— , there are a total of (3 x 7) +1 = 22 valence electrons, or 11 e1 ctron pairs. A ,_ plausible Lewis structure follows. [II—If—Ilr Since there are thre lone pairs and two ligands attached to the central 1, the electron-group geometry ar und that atom trigonal bipyramidal; its hybridization is Sp3d. Since the two ligand atoms are located in the axial positions of the trigonal bipyramid, the 1—1 — bond angle is 180°. Each I——I sigma bond is the result of the overlap of a 5 p rbital on a terminal I with an sp3d hybrid orbital on the central 1. (c) In C203; , there are a total of (2 x 4) + (4 x 6) +2 = 34 valence electr ns, (the right-hand one) is represented as follows. 0': C(sp2 )1 —C(sp2 )1 0'>:NC(sp2 )1 ~06 (2pz )1 0": C(sp2 )1 -Ob (2px) ((1) In HCO; , there are 1+4 +(3 x 6) + l = 24 valence electrons, or 12 electron pairs. A plausible Lewis structure is shown on the right. Th e' group geometry around C is trigonal planar, with a bond angle of < H—lda 120°; the hybridization is sz. The geometry around 03 is bent with a bond angle less than109.5°; the hybridization is $193. The five bonds are represented as follows: 0': 08(sp3)1——H(ls)l, 0': C(Sp2)1—Oa(sp3)l, 0': C(spz)l 0': C(spz)1 —Oc (2px)l, IZ'Z C(2pz)1 ~—Oc(2pz)1 ’—" “ a: C Mm 7 g‘ o: C (E) All of the valence electron pairs in the molecule are indicated in the sketc for the J problem; there are no lone pairs. The two terminal carbon atoms have three at ms attached to them; they are spz hybridized. This means there is one half-filled 2p orbital vailable on \ each of these terminal carbon atoms that can be used for the formation of a TC b nd. The The . central carbon atom has two atoms attached to it; it is Sp hybridized. Thus ther are two (perpendicular) half-filled 2p orbitals (such as 2 [3y and 2 19,) on this central ca on atom I olecu available for the formation of 7: bonds. One 11: bond is formed from the central arbon atom to each of the terminal carbon atoms. Because the two 2p orbitals on the centr 1 carbon atom are perpendicular to each other, these two 1: bonds are also mutually orth gonal: 3:0 Thus, the two H—C—H planes are at 90° from each other, because of the 1: ho ding in the fi; molecule. {a}, In each case, the number of valence electrons in the species is determ' ed first; this is followed by the molecular orbital diagram for each species. KK 62s 62; “2p c"2p 7‘2; 0'2; C; no. valence e' =(2x4)—1=7 KK El [D D K 52: .62.: Cy2p 752;; 752; 62;; O; no.va1encee' =(2x6)+1=l3 KK @ [E F; no. valence e‘=(2X7)-1=13 K I] N0+no.valencee‘=5+6—1=lOKK E] [if] {2}) Bond order = (no. bonding electrons — no. antibonding electrons) -:— 2 ' C: bond order = (5 —. 2) +2 = 1.5 This species is stable. 0; bond order = (8 — 5) —:— 2 = 1.5 This species is stable. F; bond order = (8 -— 5) + 2 = 1.5 This species is stable. NO+ bond order = (8 —2) + 2 = 3.0 This species is stable. {c} C2+ has an odd number of electrons and is paramagnetic, with one 1111 aired electron. 02~ has an odd number of electrons and is paramagnetic, with one un aired electron. ' F; has an odd number of electrons and is paramagnetic, with one un aired electron. NO+ has an even number of electrons and is diamagnetic. 38. (M) We first produce the molecular orbital diagram for each species. See pa e 471 int text. (a) C O C N ,‘ [’1’ 0*2p \\ I, 0*2p \\ \ / \ I, \ [I \ 1’ \\ I “ ’ ,v— — ‘\ I” —*_ \\ é" .11'* 2p ‘\\\ I ’1’ 'n- 2 \ 2p It 1 a. fl ,~=I—=__ \:\ ’ ' ,’ __ p \\ s ’ , 2p \ I \ o \\ (I, \‘ ’ \ I \\ 1’ \\ VI 029 TT2p (b) Bond order is 2.5 for CO+, 3 for CN— + ' tic, CN" is diama netic (c) CO is paramagne g etween the ((1) CG“ has the greater bond length, because there is less electron density 7‘ _‘ 4", I - u "A 7 .7 s 7 7 n n d delocahzed orb1tals 1n those specres for which bonding canno 44. (M) we expect to fin ' for species that require severa represented thoroughly by one Lewis structure, that IS, resonance forms. (a) In HCO; , there are 1+ 4 + (2 x 6) +1 = 18 valence electrons, or 9 pairs. A plausible Lewis structure has H—fi—§|> 0 (H—Cl; 9 two resonance forms. The bonding descrlptlon of HCOf requires the use of delocalized molecular orbitals. In CO32‘, there are 4 +(3 x 6) +2 = 24 valence electrons, or 12 pairs. A plausible Lewis structure has three resonance forms. The bonding description 0 C032’ requires the use of delocalized molecular orbitals. \ — 2— 2— E—C=§ __ __ 2 __ __ 2:?“19l 9 1979—91 I L9! 10! Q! (c) In CH3+ , there are 4 + (3 x 1) — 1 = 6 valence electrons, or 3 pairs. H_C_H + The ion is adequately represented by one Lewis structure; no i ll. > resonance forms exist. S o ecies Orbital Diagram 25 Bond Order -- Manetic Proert Paramanetic 1 e') m . 1? mm the MO diagrams, it is expected that NeF and NeF+ should be observable s ecies since --5tbey have non—zero bond orders. NeF' has a bond order of zero, hence it is unlik 1y that it w "ill be observed, or at best, we would expect a very loose association between t ‘ atoms tiong/weak bond). M) Since all angles ~ 120°, and since the bond angles around C total 360° (= 123° + 113° + 24°), we postulate that both the C and N atoms have Sp2 hybridization. T o resonance forms allow. up: 13 [6| Iii H—C—E—H <—-> H—C=N-—H The structure on the right would be predicted to have Sp2 hybridization on 0th the C and N atoms. For structure on the right hand side, the overlaps that form the hon . are as follows. 0': H05) —C(sp2) o‘: C(sp2)——O(2p) a: C(sp2)+N(sp2) GZN(SP2)—H(1.S') G: N(sp2)—H(ls) TE: C(sz *NQPz) Thestructure on the left is predicted to have $192 hybridization on C and Sp hybridization on N. In this structure, the following overlaps result in bonds. G:H(ls)—-C(sp2) o: C(Sp2)—O(2p) o:C(sp2)—N(sp3) o:N(sp3)—H(1s) c:N(sp3)—H(ls) n":C(2pz)— (2p,) From Table 10—2 we see the C—N bond length of 138 pm is intermediate etween a single C—N bond length (147 pm) and a double C=N bond length (128 pm), j st as we would expect for the resonance hybrid of the two structures written above. Q} in AI ‘Hwe as and hp whim/S m close eno 3h m energy +0 aliow Siam-(3004+ m‘Y'hj 0'? ‘14“?— 8-03 0-5 WA “92‘an 64’ whim/s, 'Thl's mrxmfl s-ra ‘ ng'ns O—b (makes It‘f "mare lama/{(177) 6- des‘l-a ‘ an’ “P2 0—5 (makes H’ "(63$ bandlhj") . H" (“s des-mbf’rzahbw PUShéS Lil—- above, 3. ’Tfie‘ owosffe [s 'I'Iuc ’Qor case. B, when: The (1% °‘nP ocbumls out +00 47m in energy +0 {MK 6 echi/C/y, Hem, SM: +56 npz’flpz (Tb has befi'er 0 0/000 #100 +he 1Tb coloring, H— {s [Ob/0“ {n effigy, 3\ (223 (035 (02,51 17;? Lrfirzgf BO " (bOndI'nfl 6-) - (Ml‘bondmi 6') 2 H W (025(073167294 Bo: 6-2 D s — 2 {L3 When h?’$l Ody diagth B mpglras, Wh has managed +0 fie paw whee *Hwe n$ 0 bfi'a/S We. s—fab‘luzec/ 129 muck lower eneygy 441cm +he npi during fie mhhnfl _\.\-,.__,_,,,I -, Q ...
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AK11 - (M) For each species, we first draw the Lewis...

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