General Chemistry !" #$ !" • # • $ (Chemical Bonding) • "%& '() * ! + • !" " (Lewis Structure) '() VSEPR • '() ! < ++ (Molecular Orbtial Theory; MO) • '() G+ (Valence Bond Theory; VB) '() * * ! K K 2 (Chemical Bonding) 1. 6""" (Ionic bond) 6""" LM K KS L M < M N! $ S N M&K $ EN (An attractive force that holds atoms together to form molecules) NZ [ M < S\\] (coulombic attraction) • "N • "" EN ; : *K _ → S (! K) (O*K "P M&) • "" EN =: _ → S (! K) • O N < M + (g) + X− (g) → MX(s) + lattice energy N%K & 1.S (Ionic Bond) 2.! + (Covalent Bond) 3.! K (Metallic Bond) 3 4 2. ? (Covalent Bond) 3. ? (Metallic Bond) ? LM K K $ EN ? L M ! KS *Z M (K * ( EN ) [* EN O) G+ _ * O*K"P M& • G+ _ ! K L S* S " • "" EN =: S * " _ • _ "OK M < " - - - - + - - + - + - - - - - - - - + - - - + - + - - - - - - - - Sea of - - - electrons - - - - + + - + - () - - - - - + - + - - + + - - - - - - - - - - - - - - - - - + - + - + - + - - - - - - - - - + + - + Shared - - - - electrons E"F" F 5 6 1 (Bond Energy) O ; (Average Bond Energy) KL (Bond dissociation O ; Nq " energy, D) L * *" "OK *! $ (N! ) *! $ ( N) H2(g)→2H(g) D(HfH) = 436 kJ/mol *! $ [ " C-H • → CH4(g) CH3(g) + H(g) D(H-C)CH4= 436 kJ/mol • → CH3(g) CH2(g) + H(g) D(H-C)CH3= 368 kJ/mol • → CH2(g) CH(g) + H(g) D(H-C)CH2 = 519 kJ/mol • CH(g) →→→ C(g) + H(g) D(H-C)CH = 335 kJ/mol 7 8 S" "R (Heat of Reaction) T S" "R QR L Q "T [K # S & (" & ) S #T("Z %r+) CH4(g) + Cl2(g) →→→ CH3Cl (g) + HCl(g) S" "R (∆Hrxn)L s S*<L # "PK S [ H DD rxn ∑ −=∆ ∑ • ∑ D( " & ) = 4D(C-H) + D(Cl-Cl) reactants products reactants !"" !#$ !"" !#$ • ∑ D ( Z %r+ ) = D(C-Cl) + 3D(C-H) + D(Cl-H) %"!*"+ %"&'!() products ∆ • ∆H N # Hrxn = 4D(C-H) + D(Cl-Cl) – [D(C-Cl) + 3D(C-H) + D(Cl-H)] rxn × × • ∆H N * L*K # ( < ) = (4 414 + 243) – (339 + 3 414 + 431) kJ/mol = –104 kJ/mol rxn # &[ 104 kJ/mol 9 10 (Bond Length) O ; "?_T ` LKK < " ! N OK &" M < S "$ O"$ KL "P % "$ ! +"+ • > < > " • < < < " Bond Bond Length Energy 11 12 2 _ a ! " (Bond Polarity) _ L$ M& L 106.0° a ! " L [ "Z 2 _ * *"K " "%&! +M&< EN & 104.0° " P EN &" [ ! $ "< $[S _ * K &"[S"O" GM • ° ° [ ! + & H 2O = 104.5 • H 2S = 92 Xδδδ+−−−Yδδδ- ;" EN " Y >>> X O!"! $ $ [ON v< _ *! $ H + F H F δδδ+ δδδ- 13 14 ef ;#S"$ ? f"" (Octet Rule) f"" G+ _ * ( 1. $$g " " " (Lewis Structure) [ _ KLx"qL*K< 8A)[ "P 2. ef ?_ ""$ (Molecular Orbital, MO) ! "#(% & ') • * S $* s p block 3. ef E (Valence Bond, VB) • * S " + • ! q Be B Al * f"" H He g E"F"$ " Noble Gas (8A) valence e−−− <<< 8 valence e−−− = 8 15 16 1. $$g " " " (Lewis structure) ? S $$g_Q"F" G.N. Lewis " "! +K * !" "KL!"[$ _ ! $ [NS f"" (Octet rule) L q""#Q ` (Lewis|s dot structure) N L" G+ ?S ;g S ;"#S E"F"$ _ "! +K * Qr L [ [ _ KLx"qL*K< 8A)GM ! $ O*K&! $ "P "$ !" " • "*[q G+ _ • * [$ G+ _ • * S $* s p Block Carbon Hydrogen CHCH44 17 18 3 ? S " "?_ ? S " !" "! $ 1. Q"" (S" valence electron ) • ! +L* _ " gQ ""#?_ • KM " _ (2 shared electrons) 2. $g E"F" "_""#?_ 6"""$: ;g "F"T $g g_$ "6""" • − } [$ 2 [$ (:) KL KM" ( ) } 6"""$ : $g "F"T $g g_$ "6""" ♦ _ * *" Bonding electron 3. ;"""QS Q ; ( T "" $"" ♦ _ S " non-Bonding electron ) ?Q#S 2 "F"# S Q ; T 4. E"F"#S$"" #S$8 ( S H T $ 2) H H 5. "F" ; "#S$"" (" g T 8) H C H H−C−H 6. uS g E"F" ;"" 6T$ 8 #S H H "F" ;6TT (unshared pair electron) """ N N N≡N "$` S =T " 7. g E"F" S"T $ ;6QSg S" 1. 19 20 "T ? S " " NF3 "T ? S " " HCN 1. "" " N 1. "" " C 2. g E"F" = 5 + (7x3) = 26 "F" 2. g E"F" " HCN 1 + 4 + 5 =10 "F" (g E"F" " N = 5 F = 7) 3. Q ; T "" $"" 3. Q ; T "" $"" ; F N F F N F H C N ,- F F 4. "F" """ #S$ 8 ( " 2) 4. "F" """ #S$ 8 H C N F N F F 5. "F" ; "#S$"" (10-10 = 0) 5. "F" ; "#S$"" (26-24 = 2 .!"/$012/1$34 "F") 6. "F" ;6TT """"$` (N) S F N F F N F F N F =T " g"" "F"$Q ,- ,- F F F H C N H C N H−C≡N 21 22 S" S "f"" g_{" (Formal charge) 1. ?_ ; "F"y ; T g_{" y T T g E"F" " ""Q ; $ """#? S " y a • ClO2 "F" T $ 19 • NO "F" T $ 11 ! "?_"T T ` • NO2 "F" T $ 17 g_{" """ 2. ?_ ;"" "F"S" T 8 • = − − 1 BNV BF3 B "F"T $ 6 formal charge 2 eee • BeH Be "F"T $ 6 2 • V E"F" """Q ; 3. ?_ ;"" "F" T 8 • N E"F" ;6T6QS S • PCl5 "F" T $ 10 F • B E"F"!Q ; S "$""! • XeF4 "F" T $ 12 F S F F • SF4 "F" T $ 10 23 24 4 "T g g_{" "T"" ?EE (Resonance) | [IO3] O−−−I−−−O *! $ KLS "P [O "S O 1 CO2 SO2 +1 -1 -1 +1 • −−−1 +2 −−−1 ≡ − − ≡ I = 7 2 ½ (6) = +2 O−−−I−−−O O≡≡C −−OO = C = OO − C ≡≡ O • O = 6 6 ½ (2) = -1 +1 +1 O S S [$ = +2 1 1 1 = -1 −−−1 O O -1 O-1 O | [NHH 3C 2COO] Q <[O #+ & R ?EE ! H H O [O [ [ O KL" + H−N−C−C N G+ 5 3 - [ _ * H H O P [N P S[N 25 26 ?EE (Resonance) ? S Lewis ;y66QS K * [!"* N!" !" " O3 +1 +1 NSS "$ K & O O 1. NS ) "$ O O O O -1 -1 2. !" [$\+ O "$ [ K O &" 3. EN "< [$\+ N " ! $ O3 S & 2 !" 4. S [$\+ !"!GG+ (Resonance structure) O≡ C −−− O O = C = OO − C ≡≡≡ O CO2 +1 0 -1 0 0 0 -1 0 +1 1.278 Å O 1.278 Å − N N N N N N N N N O O N3 -2 +1 0 -1 +1 -1 0 +1 -2 27 28 ef ~_T"F"# E ~ "_T"F" Valence Shell Electron Pair Repulsion(VSEPR) L'() * ( < KL ") N O<! $ KLS M ! G+ _ " $ & $[ [O ! !"! $ [M&<[O $ _ * _ " _ ! S[ON Z $ _ M& $ • 2 _ [q G+ _ & _ (P $ _ *K [ <[M • _ N $ (< _ ; electron pair) "PZ $ _ LSS ) ♦ "F" S (2, 4, 6 _ L , <, " ) $ _ >>> >>> >>> >>> ♦ "F"=T?QQQ ; (2 _ ) =T?QQQ ; =T Q ; "F"Q ; ♦ "F"?QQQ ; (1 _ ) $ _ "[ P EN • $ _ [[ *KK "$ L*K M& (Z [ ) Z "$ Q u ; _Q 29 30 5 gQ T "_T"F"(m+n) =T ?_?Q VSEPR _T"F"" gy"F" S "6T S F6QS 1. "< !" " 2. "< AXmEn 180° • A • X 120° ! m L g _T"F" ; S • E $ _ SS " 109.5° ! n L g _T"F" ;6T6QS S 3. O[ OK $ _ (m+n) 90,120° 4. [ OK< _ ! ( L& "$ ) KL _ ! ( L& "$ ) 90° 5. O<! $ ! <[[ OK 31 32 =T "?_ =T "?_ 2 $ _ (n+m=2) 4 $ _ (n+m=4) • AX2 +" • AX4 4"89,+ 3 $ _ (n+m=3) $,89.$ • • AX3 :;; XA 3E 8$=> $,89.$ X• A 2E $<$" (<120°) • AX E 2 2 $<$" (<109.5°) 33 34 =T "?_ =T "?_ 5 $ _ (n+m=5) 6 $ _ (n+m=6) • AX 8$=?@0> • AX 5 $,89.$ 6 4":1=,+ X• A 4E =, X• A E 8$=> 5 89,89.$ !48 • AX3E2 89,89.$ • +" AX4E2 :;; X• A 2E3 35 36 6 "T =T ?_ "T =T ?_* = " = AXmEn T_T =T ?_ ! $ 1 *K [ "F" CH4 H H H C O H H C H AX E 4 0 H H AX4 AX2E2 ;S _" NH3 E H ∼∼∼ ° AX E 109.5 H N H 3 1 ∼∼∼104.5° 37 38 _ ; ;6* ~ "T EN T"_* EN (EN $) 120°°° >120°°° >120°°° PI PBr PCl PF AX3 3 3 3 3 <120°°° <120°°° EN(X) 2.66 2.96 3.16 3.98 H Cl angle 102.0 101.5 100.3 97.8 H 109.5°°° H >>109.5°°° <109.5°°° °°° H >109.5 EN (EN $) H <<109.5°°° H X H >109.5°°° AsH PH NH <109.5°°° AX3 3 3 3 A EN(A) 2.17 2.19 3.04 X 90°°° >90°°° °°° X <90 angle 91.6 93.8 107.0 °°° 120 >120°°° 39 40 _ = " * a ! "?_ (Polarity of Molecule) "PO"< "S [$! $ a ! "?_L"%&"$ (net dipole)$ *! $ 104.5°°° 90°°° 107°°° AX E AX E AX E 2 ? 3 ? 4 ? "%&! $ KS ! "%&$ + AX H O 4 AX2E2 110°°° 104°°° | || 118°°° H–C–C–O–H AX3 | H 41 42 7 "T a ! "?_ 2. ef ?_ ""$" (MO Theory) BCl ef ?_T ""$ (Molecular Orbital Theory) 3 ! +! * + ! $ NH3 "" "" ?_ AO + AO MO CHCl3 ""$ "?_ (MO) L < _ * SF ! $ [+ (AO) 5 Z " (Linear Combination of Atomic Orbital, LCAO) HCN [O MO M&[O AO &K 43 44 S ?= ""$ S ?= ""$* + ! $ [GK L (overlap) AO ES" ;" """$ """ (AO Overlap) $$ (Bonding): N AO ;" ( ) " L AO GK L[ N MO Q""$# ;"""; ! u ! • $$ (Antibonding): N AO ;" ( )T $$ (bonding molecular orbital, BMO) + [ Q""$# ;"""Q u S" ( ;) *KM&* LK "P M& • $$S (antibonding molecular orbital, AMO) + ~~Q$ "?= ""$ (Molecular Orbital Diagram) LZZ " [ *KM&* LK "P MO AO ES" ;" " AO gQ !6QS ;" 1sA − 1sB Antibonding antibonding • AO * • AO K" Energy 1s 1sA B • AO < v K" 1s + 1s Bonding A B bonding 45 46 ES" ;" """$* Q "?= ""$ <+ * MO M&< AO y sigma bond ( σ,σ*): GK L 1-lobe Aos z (head-on overlap) x σσσ bonding σ antibonding pi-bond ( π,π*): GK L 2-lobe AOs 2s orbital GK LK+ A B (side-on overlap) πππ bonding πππ antibonding πππ bonding delta-bond ( δ,δ*): GK L 4-lobe AOs A(p ) B(p ) A(s) B(s) A(s) B(px) x x A(py) B(py) A(s) B(py) δδδ bonding 47 48 8 Q "* Molecular Orbital Diagram* ~~Q$ "?_ ""$ LZZ Sigma antibonding (σ*) Pi antibonding (π*) " MO AO AOs [" KLO • O [S AMO (E ) • " [S BMO (E ) E >>> E >>> E Sigma bonding (σ) Pi bonding (π) AMO AO BMO P AO GK L EAMO EAO EBMO "P*GK LM& s+s px+px py+py σ > π > δ 49 50 Q$ " MOs* ES" ;" " AOs AOs Q$ T AOs Q$ T Sigma bonding Pi bonding E > E > E E > E > E > E AMO AO BMO AMO AO-H AO-L BMO s+s py+py • • ∆Ed: destabilization energy AMO g $S AO-H • • ∆∆∆Es: stabilization energy BMO g $S AO-L px+px y Q """$ !$ ES" x AO: Atomic orbital ;" " AO BMO: Bonding Molecular Orbital z AMO: Antibonding Molecular Orbital 51 52 Molecular Orbital Diagram $g_"F"# MOs σ 2 σσσ 2 σσσ 2 πππ 4 πππ 4 σσσ 2 EE--configurationconfiguration: ( 2s) ( 2s*) ( 2px) ( 2p) ( 2p*) ( 2px*) 1.