Chapter 7 Atmic Structure and Peridicity ATOMIC ORBITAL MODEL OF THE ATOM Be able t draw rugh sketches f s, p and d rbitals with different principal quantum numbers ELECTRONIC CONFIGURATIONS Knw the difference between cre electrns and valence electrns PERIODIC TRENDS Inizatin Energy Electrn Affinity Atmic radius Inic Radius METALS AND NON-METALS Physical prperties Chemical characteristics MAGNETISM Paramagnetism Diamagnetism Chapter 8 Bnding Culmb s Law - Frm is Energy = k*q 1 Q 2 /r Be able t answer questins in which charges r distances are varied Be able t explain bnding diagram (Figure 8.1) Electrnegativity Knw fr Li thrugh F (1.0 t 4.0 cunt by 0.5) Knw H (2.1) Knw Inic vs cvalent vs plar cvalent calculate Electrnegativity difference 0-0.4 nn-plar (C-H bnds are nt plar, all ther 0.4 differences are e.g. H-S) 0.4-1.9 plar > 1.9 inic Classify the fllwing (inic, etc) CO 2 H 2 O BH 3 BeS Draw Lewis Dt Structures Duet rule (hydrgen nly can have 2 electrns! One bnd!!!) ctet cases (CH 4 ) extra electrns (XeF 2 ) electrn deficient make a ring (t accmmdate 2 electrn deficiency)
add a duble bnd (t accmmdate 2 electrn deficiency) vilate ctet rule BCl 3 dd number f electrns NO 2 (put radical n least electrnegative element) RESONANCE draw all pssible frms Charges cunt thse electrns!!! Put brackets arund!! Inic KClO 4 d inic transfer first [K] + - take electrn and add t ClO 4 - nw d ClO - 4 nrmally Apply VSEPR Thery t determine mlecular shape Cunt ttal bjects arund a center atm Remember - a single, duble, and triple bnd are ne bject 2 = linear 180 3 = trignal planar 120 4 = tetrahedral 109.47 5 = trignal bipyramidal 120 at equatr, 90 axial 6 = ctahedral 90 If n lne pairs, yu have yur final mlecular shape If lne pairs, remve frm yur base shape and generate yur final mlecular shape REMEMBER lne pairs ccupy mre space than atms 1 lne pair 2 lne pairs 3 lne pairs 3 = trignal planar bent linear - 4 = tetrahedral trignal pyramidal bent linear 5 = trignal bipyramidal see saw Tee linear 6 = ctahedral square pyramidal square planar Bnds Example (Shape) Diagram 2 BeCl 2 (Linear) 3 BF 3 (Trignal) 4 CH 4 (Tetrahedral) 5 PCl 5 (Trignal bipyramidal)
6 SF 6 (Octahedral) Bnds LP's Example (shape) Diagram 3-D 2 1 O 3 (bent) 3 1 NH 3 (trignal pyramidal) 2 2 H 2 O (bent) 4 1 SF 4 (distrted tetrahedral; see-saw) 3 2 ClF 3 (T-shaped) 2 3 I 3 - (linear)
5 1 BrF 5 (square pyramidal) Identify if a bnd is plar (E.N. difference greater than 0.5) Identify if a mlecule is plar CO plar bnd and plar mlecule H2O plar bnd and plar mlecule CCl4 plar bnds but nn-plar mlecule Symmetric shapes that cancel ut plarity Nn-plar plar Linear O=C=O O=C=S Trignal planar BCl 3 BCl 2 F Tetrahedral CCl 4 CCl 3 H Trignal bipyramidal SCl 5 SCl 4 Br Octahedral - PF 6 PF 5 Cl - Sizes f Ins Knw relative sizes f ins (e.g. rank frm smallest t largest: S +6, S, S -2 Knw trends in size increase ging dwn a grup decrease ging acrss a perid Rank within an iselectrnic series smallest t largest: Sr +2 Rb + Br - Se -2 ) Lattice Energy Brn Haber Cycle Knw steps f the cycle and relative magnitudes i.e. Na(s) Na(g) make slid int gas Na(g) Na + (g) make int catin Cl 2 (g) 2Cl(g) break the bnd Cl(g) Cl - (g) make anin (add electrn) Na + (g) + Cl - (g) NaCl(s) lattice energy!! Same steps - with enthalpy terms Na(s) Na(g) enthalpy f vaprizatin psitive r negative? Na(g) Na + (g) inizatin enthalpy psitive r negative? Cl 2 (g) 2Cl(g) bnd enthalpy psitive r negative? Cl(g) Cl - (g) electrn affinity psitive r negative? Na + (g) + Cl - (g) NaCl(s) lattice energy! psitive r negative? Als, which have the largest magnitude? Cvalent Bnd Energies
Bnd lengths and Bnd energies Shrter mre energy 120pm =? 134pm =? 154pm =? which is single, duble, triple Use Cvalent radius t calculate bnd lengths Chapter 9: Cvalent Bnding HW10 LOCAL ELECTRON MODEL Cmbines Lewis Dt Thery with mixing f atmic rbitals t create hybrids Hybridizatin sp, sp 2, sp 3, dsp 3, d 2 sp 3 (knw gemetries and angles) Failure f L.E. mdel (it must resrt t resnance t fudge the results) MOLECULAR ORBITAL THEORY (M.O. Thery) Use atmic rbitals and create sigma and pi mlecular rbitals Ultimately, cmbine MO thery with lcal mdel allw mixing and allw hybridizatin and get better verall explanatin f bnding Understand hw MO thery explains the delcalizatin f pi rbitals Calculate Bnd rder, determine magnetism (para r diamagnetism) Sigma and Pi Bnding be able t identify and cunt bnds sp bnding in tw directins H-C C-H Carbn is sp hybridized (180 ) sp 2 bnding in three directins BH 3 (n lne pair, just a three rbitals at 120 sp 3 dsp 3 bnding in fur directins CH4 r NH3 (remember, NH3 has a lne pair in 4 th directin) tetrahedral angles f 109.5 bnding in 5 directins trignal bipyramidal three at 120 t each ther in same plane, the 4 th and 5 th at the tp and bttm e.g. XeO 3 F 2 d 2 sp 3 bnding in six directins - ctahedral e.g. PF 6-1