Chem 111 1st Edition Exam # 3 Study GuideCh. 5Resonance structures: when 2+ equivalent Lewis structures can be drawn for one compound, same arrangements of atoms different arrangement of bonding pairs of electrons ex. O3(ozone)Formal Charge: determined by difference between the number of valence electrons in the free atom andthe sum on lone pairs and ½ the number of electrons in bonding pairs ex. H2O H has 1 e- normally, when bonded in H2O is has a formal charge of 0 because it has no lone pairs and is only involved in a single bond.Determine the best structure by minimizing FC and more negative FC on the more electronegative elementKnow the exceptions to the octet rule! Usually occurs when involving a very electronegative element. GROUPS 2 AND 3 ON THE PERIODIC TABLEBond energy: shorter the distance between the atoms(number of bonds), more energy you need to break itSteric numbers: 2=linear can only be linear 3=trigonal planar can be trigonal planar or bent4=tetrahedral can be tetrahedral trigonal pyramidal or bent5=trigonal bipyramidal can be trigonal bipyramidal seesaw t-shaped or linear6=octahedral can be octahedral square pyramid or square planarDipole Moment: HOW POLAR IS THIS STUFFSigma Bonds: ALL SINGLE BONDSHybridization: mixing of atomic orbitals to generate new sets of equivalent orbitals that form covalent bonds with other atoms EX sp, sp2, sp3(1 part s, 3 parts p)Pi bonds: ANY BOND AFTER A SINGLE BONDA double bond counts as 1 sigma bond and one pi bondThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.Ch. 6 Intermolecular forces: Dispersion(everything), Dipole-dipole(polar molecules), Hydrogen bonds(H bonded to a F,O,N) THINK FUNFactors affecting strength of dispersion: size(bigger the better) and shape(high surface area high dispersion)Boiling Point: High molar mass=high boiling pointBoiling point gets higher when you move down the list of the strongest attractions= dispersion will lead to lowest, dipole dipole will have higher, H bonding will have highest boiling pointSolubility: solute=DISSOLVING IN(salt in salt water), solvent=DOING THE DISSOLVING(water in salt water)Ion-dipole: force attracting an ion to a highly polarized molecule USUALLY INVOLVING WATER and an ion attracted to either the negative oxygen or the positive hydrogensLIKE DISSOLVES LIKENONPOLAR DISSOLVES NONPOLARPOLAR DISSOLVES POLARIONIC DISSOLVES POLAR (and vice versa)Solubility Behavior: hydrophobic=hates water, hydrophilic=loves waterIclickers for help: Which of the following is polar: CH4, NH3, BF4, PCL5Answer- NH3 all of the others are equally polar overall, lone pair makes NH3 polarSP3 involves the steric number of 4 which is tetrahedrals, trigonal pyramidal and bent geometric structuresThe bond angle between 1 p orbital and another is 90 degreesThings with double bonds will have smaller bond anglesThe number of hybridizations= the steric numberWhich molecule contains a pi bond? C2H2 or C2H6Answer: C2H2 you need to have a double or triple bond in order to have a pi bondDispersion forces are the only forces holding nonpolar molecules togetherWhich has the lowest boiling point? CH3COCH2CH2CH, CH3CH2CH2CH2CH2CH3, CH3CH2CH2CH2CH2OHAnswer: the middle one, the first is polar and has dipole dipole forces and the third has hydrogen bonding, the middle only has dispersion forcesLike forces= solution, nonlike forces=no solutionOrder of increasing boiling point=H2(disp)<Ar(disp. But higher molar mass)<PF3(dipoledipole)<HF(Hbonding)Least soluble in water: NaNO3(ionic), HCl(ionic), NH3(polar), CH4, NF3(polar)Answer: only CH4 is neither ionic nor polar and using the like dissolves like as written above, would be the only one to not dissolve in water because it is happy the way it