Name: Period: Date: BONDING NOTES ADVANCED CHEMISTRY

Transcription

1 Name: Perid: Date: BONDING NOTES ADVANCED 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! VALENCE ELECTRONS: -Usually energy level AND electrns added tgether -Ex: -Mre Ex: ELECTRON DOT STRUCTURES: -Hw t draw: 1) Determine the # f 2) Write the element 3) Add ne at a time t each side f the symbl shw as 4) Until they are frced t ( e- max) EXAMPLE: -Mre Practice: 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 ) 1

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-. -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 2

3 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 -Metals hld n t their valence e- -Psitive ins (catins) are in a *ELECTRONS ARE TO!! 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!! 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 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!! 4

5 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:. -Example: Write the dt structure fr:. -Example: Write the dt structure fr:. 5

6 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: 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: 6

7 -TRIGONAL PLANAR: -TETRAHEDRAL: -TRIGONAL PYRAMIDAL: -BENT: 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: 7

8 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 = 3.1 -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!! 8

9 -Example: 2 Plar Bnds ( ) Highly electrnegative pulls the e- away frm the shape mlecule *DRAW: - Example: 2 Plar Bnds ( ) Highly electrnegative pulls the e- away frm the shape / diple mlecule *DRAW: 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: 9