University:
Mississippi College
Course:
CHE 141 | General Chemistry I
Academic year:

2022
Views:

234

Pages:

3
Author:

Abby D.

theoriesregardingchemicalbondingLewis Theory (1st)USEPR Theory(2nd) Valence Bond Theory(3rd)Describe the type &Describes the bondDescribes the type of orbitals(c)placement of bonds inangles and thus, the used for bonding.molecule.shape of the molecule.H2Osingle bonds..7SO"bent"H 10thsHHH2-109.HLewis Theory: we draw Lewisce - dot) Structures to represent atomsor molecules! each dot represents 1 valence e-L.S.'S: for atoms:L.S.'S for molecules:Key Pt: Bonds are formed in order to lower theHAlCenergy of the two atoms.Atoms are happy e (lowE or stable) when theyhave a"full" valence Shell/ or bitals!!Ijwize's(aduet) H ISHe71U asisIsneeds to be 8 valeAll other atoms: C -15 25228 2""octect"4vale-Br [Ar]4520110Sneeds one more to beL.S.'S for molecules:lonic compoundsle-KCICI:L.S.: K+:CI:15252 152 2522p3323p31325 le-U-1+1"Lizs": Li.S:L.S.:2Li+12-nmLi.le-2-A12O3AlL.S.: 2A13*3:O:AlJ 35ge-(7AL.S.SforMolecular9Compounds(covalentFF2"bonds)key Pts.Core e- not depicted.F:Intranucieor space2, valence e-'s only.3. In a molecule, all vale-exist in pairs.- L.S.4. Lone pairs us. Bonding pairsbondingLone pair (6)5. The shave e- COUNTPairtowards the octet/duet forboth atoms!!H2O2N2H. OHOcN:H- H".0: : 02 N: IISingle bond(2 sharede-- O: UTriple bonddouble bond(strongest & shortestCOV. bond)Stronger 8 Shorterthan Single bonds)S+3(7) = 26/2 =Steps for drawing L.S. for any molecules not ions here)NF313 pairsD Arrange the atoms on paper (grid.)usually2) Count the total # vale-s in the malecules andcentralatom/unless H)divide by 2 toget # of pairs.of cleast electronegative).usually on one3) Connect atoms to Ctrl atomw/-(sB's)"SCN" 1) keep that order4) Add remaining pairs as Lone pairs, 1st - terminalatoms, then Ctrl atom. satisfying atoms as you go!2?'s 1) Did you use all pairs?2) Is every atom satisfied?pain=15) If you "run out of pairs" reassign LP's asbonding pairs to serve both atoms!6) If you have Xtra pairs, add them as L P's to the Ctry atom, whichwillgiveitan"expandedOCtet"fine,stableforatoms(period)in3rdperiodic&below.32 R334+2(6)=16/2=(8p+CO2Ctrlnot"all have 8e. :IQ:0= C= O:S+6=11-1=10e-125p -NO+ Hoste-4b+N- -NO::7+4(7) = 35 +1= 36/2=18ICl4 -gains ef-:Cl:C1:Exceptions to octet rule:1) expanded Octet2) Incomplete Octet (L 8e-'s & still satisfied (i)B&Be3+21=2412=12p2+ 14 =16/2=8pBF3&Be F2E-B-F:F-Be-1 F:Ginappy wl 2 pairschappy W/3 pairs