Name: Period: Date: BONDING NOTES HONORS CHEMISTRY

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1 Name: Perid: Date: BONDING NOTES HONORS CHEMISTRY Directins: This packet will serve as yur ntes fr this chapter. Fllw alng with the PwerPint presentatin and fill in the missing infrmatin. Imprtant terms / ideas are in all capitals and blded! CHEMICAL BOND: -Types include,, r -Differences in determine the bnd type IONIC BOND: -Each atm achieves a cnfiguratin ( valence shell) -Usually between a and a -Frmula Unit: whle-number rati f ins in an inic cmpund (ex: NaCl r MgCl 2 ) Inic Bnding -Hw t shw using Electrn Dt Structures: 1) Draw the fr each element in the inic cmpund 2) Determine which element will and which will and hw many 3) Use t shw the e- being t an empty space n the anin s dt structure 4) Cntinue until each element has a add mre f each element as needed -Example: Shw the electrn dt structures fr and using arrws t indicate the transfer f e-. -T write the fr the cmpund: write the element symbl fr the catin fllwed by the anin symbl t indicate the f each use (nne needed if just ne)!! -Example: Shw the electrn dt structures fr and using arrws t indicate the transfer f e-. 1

2 -Mre Examples: Shw the electrn dt structures fr each pair and shw the transfer f electrns using arrws. Be sure t include the charge n each in after the transfer and write the frmula unit. and and and and Inic Cmpunds -Frmed frm and ins bnded tgether -Knwn as -Frmed frm regular arrangement f frmula units Prperties f Inic Cmpunds 1) bnded: strng attractin between the ins 2) Slid lattice structure 3) melting pint and biling pint due t the strng between ins and the structure 4) in water / DISSOCIATE (break apart int ) 5) Cnduct when melted r disslved in water (because they frm ) t rderly when 6) Extremely if yu hit them hard enugh they will because they dn t want t bend and there will be a strng frce METALLIC BONDS: -Frces f attractin hld tgether -Nt -Have prperties t inic cmpunds 2

3 -Metals hld n t their valence e- -Psitive ins (catins) are in a *ELECTRONS ARE TO!! Prperties f Metals 1) 2) 3) -All due t the fact that their are! -Electrns allw the atms f metals t like! -Crystalline Structure Metal atms are very and rderly like a ALLOYS: -Frmed by a mix f ingredients and then -Examples: (Cu and Zn), (Cu and Sn), and (Fe, C, etc.) Why Make Allys? -Prperties are t individual elements -Sterling Silver (92.5% Ag, 7.5% Cu):, mre than pure Ag / enugh t wrk -Steels: resistant, ductile, hard, tugh, and COVALENT BOND: -Invlves tw -Knwn as cvalent r cmpunds -MOLECULE: f atms jined by a bnd -DIATOMIC MOLECULES: elements that exist as atms Ex: H 2, N 2, O 2, F 2, Cl 2, Br 2, and I 2 3

4 Prperties f Cvalent Cmpunds 1) Lw and pints 2) Dn t usually electricity 3) Nt usually sluble in (sme disslve but dn't dissciate!) 4) Dn t frm crystals (mst r at rm temperature) Types f Cvalent Bnding -There are types f cvalent bnds: 1) SINGLE: 2) DOUBLE: 3) TRIPLE: *Remember the ctet rule electrns are needed!! Bnd Length -As the number f bnds between tw atms, the bnd length the bnds becme and!! Mlecular Dt Structures -Visual representatin f hw the are tgether in a mlecule -Shws valence e- as can see f cvalent bnd as well (sharing f dts = a bnd) -Hw t draw a structure: 1) Determine the number f available fr the entire mlecule frm the amunt each element has... This is the # f e- that MUST be in the final structure 2) Psitin any C r N atms in the center With atms ther than C r N, put the electrnegative atm in the center (usually the atm that there is f in the frmula)... H never in center unless it s the nly element 3) Whatever atms are remaining in the frmula g the center (evenly distributed when pssible) 4) Any atms next t the center need t at least a pair f electrns between the atms (cvalent bnding)... Insert pairs f e- between bnded atms 4

5 5) Give each atm a cmplete ctet by adding (lne) pairs until each atm is happy with its number 6) Ttal the e- in the mlecule and see if ttal frm is reached... If s, then dne 7) If the #, add duble r triple bnds and remve pairs... If the #, add lne pairs (extra) t the center atm *DO NOT an atm s valence shell Ex: H nly wants electrns!! HONC Certain elements USUALLY have a specific number f (shared pairs) in a mlecule!!! - bnd - bnds - bnds - bnds -Atms still need a!! ** IF YOU LOVE!! Mlecular Dt Structures -Example: Write the dt structure fr:. -Example: Write the dt structure fr:. -Example: Write the dt structure fr:. 5

6 -Example: Write the dt structure fr:. -Example: Write the dt structure fr:. Exceptins t the Octet Rule -If the number f electrns desn't wrk ut 1) H - full valence shell is e- 2) B - generally satisfied with valence e- 3) Be - generally satisfied with valence e- 4) N - can be satisfied with valence e- 5) As, S, I, Se, and P can expand their ctet t have,, r valence e- Structural Frmulas -Uses a t represent a cvalent bnd -Unshared pairs still shwn as -Examples: RESONANCE STRUCTURES: -Fund in many bnded mlecules -Ex: r -Draw bth: 6

7 VSEPR THEORY: -Mlecules are really, nt -Unshared pairs are held t the atm and they the bnding pairs which pushes them tgether -Types f e- pairs: BONDING PAIRS è LONE PAIRS è *LONE PAIRS REPEL THAN BONDING PAIRS!!! Cmmn Mlecular Shapes (Give an example, draw mdels, and indicate bnd angle fr each) -LINEAR: -TRIGONAL PLANAR: -TETRAHEDRAL: -TRIGONAL PYRAMIDAL: -BENT: 7

8 -TRIGONAL BIPYRAMIDAL: -OCTAHEDRAL: -SQUARE PYRAMIDAL: -SQUARE PLANAR: ORBITAL HYBRIDIZATION THEORY: -Cvalent bnds frm when atmic rbitals -Mixing f s, p, and smetimes d rbitals that allws bnds t frm -Ex: / hybridizatin Shape Hybridizatins -LINEAR (2 attached): -TRIGONAL PLANAR (3 attached): -TETRAHEDRAL (4 attached): -TRIGONAL BIPYRIMIDAL (5 attached): -OCTAHEDRAL (6 attached): Depends n which f rbitals are being! 8

9 Multiple Bnd Hybridizatins -Single Bnds: Duble Bnds: Triple Bnds: SIGMA (σ) BONDS: - bnds -Ex: PI (π) BONDS: - than sigma bnds -Duble bnds = sigma / pi -Triple bnds = sigma / pi -Ex: / BOND ENTHALPY: -Bnds BREAKING = -Bnds FORMING = -Change in enthalpy ( ) fr a reactin can be fund using the bnd energies: ΔH rxn = Σ(energies f bnds ) Σ(energies f bnds ) -Hw t Calculate fr a Reactin: 1) Draw the fr all the substances in rder t see which bnds will break and frm 2) Sum the f ALL f the bnds that are brken and the sum f the energies f ALL f the bnds that are frmed 3) Amunts f each (frm the reactin ) need t be cnsidered when calculating 9

10 -Average Bnd Energies (kj/ml): H-H 432 H-F 565 H-Cl 427 H-Br 363 H-I 295 C-H 413 C-C 347 C-N 305 C-O 358 C-F 485 C-Cl 339 C-Br 276 C-I 240 C-S 259 N-H 391 N-N 160 N-F 272 N-Cl 200 N-Br 243 N-O 201 O-H 467 O-O 146 O-F 190 O-Cl 203 O-I 234 F-F 154 F-Cl 253 F-Br 237 Cl-Cl 239 Cl-Br 218 Br-Br 193 I-I 149 I-Cl 208 I-Br 175 S-H 347 S-F 327 S-Cl 253 S-Br 218 S-S 266 Si-Si 340 Si-H 393 Si-C 360 Si-O 452 C=C 614 C C 839 O=O 495 C=O 799 C O 1074 N=O 607 N=N 418 N N 941 C=N 615 C N 891 Higher energy = bnd! -Example: Calculate the change in enthalpy fr the reactin using bnd energies. -Example: Calculate the change in enthalpy fr the reactin using bnd energies. -Example: Calculate the change in enthalpy fr the reactin using bnd energies. 10

11 -Example: The frmatin f ethyl butanate, ne f the cmpunds that give pineapple its flavr, is prduced accrding t the reactin belw. Calculate the change in enthalpy fr the reactin using bnd energies. Bnd Plarity -Cvalent bnds invlve the f electrns but nt all atms share! -Electrns are in a between atms NONPOLAR COVALENT BONDS: -Cmpunds in water ( like disslves like ) -LOWER and than plar cmpunds -Ex: POLAR COVALENT BONDS: -Cmpunds are in water ( like disslves like ) - biling and melting pint than nnplar cmpunds -Ex: Plarity -Difference in (ability f an atm t pull e- twards itself) between the atms determines what type f bnd frms Electrnegativity Difference Type f Bnd Example S-Se = Cl-P = 1.4 > 2.0 Na-F =

12 -Example: = electrnegativity f 2.1 = electrnegativity f 3.0 è difference is 0.9 Cl shared e- giving it a slight charge H has shared e- time giving it a slight charge PARTIAL CHARGES: -Much less than a r in bnding -DELTA dentes partial charges (, ) -Written as: *Having a and the right make HCl a and it is a DIPOLE ( )!! Plar Mlecules -Fr a mlecule t be POLAR it must have: At least plar bnd shape ( ) r asymmetrical atms **Just having des make a mlecule plar!! -Example: 2 Plar Bnds ( ) Highly electrnegative pulls the e- away frm the shape mlecule *DRAW: 12

13 - Example: 2 Plar Bnds ( ) Highly electrnegative pulls the e- away frm the shape / diple mlecule *DRAW: INTERMOLECULAR ATTRACTIONS: - than inic r cvalent bnds (shw as a instead f a slid line) -Make and cmpunds pssible -Cntribute t the f the substance *NOT!! -VAN DER WAALS FORCES: 1) LONDON DISPERSION FORCES: due t the mvement f in mlecules when are mre abundant n ne side f a mlecule, there is a weak frce f t anther mlecule ( ) Example: 2) DIPOLE-DIPOLE INTERACTIONS: happen when mlecules are attracted t each ther attractin between the charges ( ) Example: -NON VAN DER WAALS FORCE 3) HYDROGEN BONDING: strng attractins between the end f ne diple and the,, r atm f anther diple ( ) Like a interactin, nly Respnsible fr determining f Example: 13

14 Attractins and Prperties -Wide range f prperties amng cvalent cmpunds due t varying intermlecular -NETWORK SOLIDS: - melting pints ( r higher) -T melt, the cvalent bnds need t be -Example: 14