CHE 101Final Study GuideChapter 10Bonding and Lewis Structures- Want 8 VE by sharing or having on its ownTypes of Bonds1. Metallic- share electrons because metals lose electrons easily2. Ionic- transfer electron to get octeta. Metals lose and nonmetals gainb. Stability: more positive = more stable3. Covalent- share electron in molecular compoundsa. More electrons = strong bond = short bond4. Possible Bond DistributionsElectronegativity - Bonded atoms ability to attract electron in bond (strength of bond)- Higher EN means better at attracting electron- EN determines amount of sharingo Nonpolar covalent: electron shared equally (0-0.4, identical nonmetal atoms)o Polar covalent: electron shared unequally (0.4-2, different nonmetal atoms)o Ionic: electron transferred (2-4)- Polarity describes electron sharingDipoles- Partial negative charge = more electrons around ion- Partial positive charge = less electrons around ion- Atom with higher EN gets partially negative endLewis Structures- Show covalent bonding, use VE and octet rule- Exceptions to octet rule:o Incomplete octet- EN too low to get more electrons Be has 2 VE and stable with 4 B has 3 VE and stable with 6o Expanded/Break octet- possible for electrons in periods 3-6 Unfilled d-orbital or large size of central atomDrawing Lewis Structures1. Calculate total VE in moleculea. V= # of atoms(VE) + # of atoms(VE) = charge2. Determine central atom, least EN atoma. H never central atom, sometimes can have multiple centralsb. C always central and rarely has lone pairs3. Draw skeleton structurea. Single or multiple bonds, try for symmetry4. Fill in octets with lone pair electrons to outeratoms then central a. # of electrons must equal V (from step 1)5. Calculate formal charge (FC)a. FC = VE –(# unshared electrons – (#shared/2))b. Must add up to charge on moleculec. Only indicate non-zero chargeResonance- More than one structure can be drawn because of…o Presence of multiple bonds and/or central atom can break octet with outer atoms capable of multiple bonds- Atoms stay but redistribute electrons - Use FC to rank resonance…o Best structure has lowest FC and/or negative FC is on most EN atom- Resonance structures blend but don’t change back and forthPolyatomic Ions and Acids- When turning molecule into acid you add H- H attracts to negative part of moleculeo Add to structure and determine best place by FC- H almost always attaches to O in acids2A3A4A5A6A7A# of bonds 2 3 4 3 2 1# of lone e- pairs 0 0 0 1 2 3Chapter 9Molecular Geometry and Bond Theories- Geometry creates bond angles, electronic geometry is arrangement of electrons around central atom and molecular geometry is arrangement of atoms around central atomElectron Domains- # of bonding and lone pairs around central atom- Resonance structures have same # of domains- Each central atom has own set of domains- Diatomic doesn’t equal domainVSEPR1. Electronic geometry determined by # of domains2. Molecular geometrya. Don’t consider lone pairs, lone pairs and double/triple bonds decrease angle between bonding atomsb. Molecules with more than 1 central atom means entire molecule is combo of all CAs,investigate separatelyMolecule Polarity- Distance of electron in entire molecule- Depends on dipoles: look at direction and bond strengtho Arrows cancel = non-polar, don’t cancel = polarMolecule Polarity and Resonance- Merging resonance structures may change polarity of molecule- Individual atoms polarities may cancel and be non-polarValence Bond Theory- Covalent bonds form when orbitals of 2 atoms overlap- Region is between nuclei and filled with shared electrons pairs, mix orbitals1. Electron in overlap region have opposite sign2.Greater overlap = stronger bondo p, d, and f orbitals align along long axis3. Works for diatomic (linear) molecules- Orbital hybridization comes from mixing orbitalso sp, sp2, sp3, sp3d, sp3d2o # of original atomic orbitals = # of hybrid orbitalsCreating Hybrid Orbitals1. sp hybrid- 2 orbitals make linear electronic geometry and 2 unhybridized p-orbitals left over2. sp2 hybrid- 3 orbitals make trigonal planar electronic geometry and 1 unhybridized p-orbital left over3. sp3 hybrid- 4 orbitals make tetrahedral electronic geometry and have 0 unhybridized p-orbitals left overShortcut for Predicting Hybridization- Draw lewis structure, determine domains, hybrid superscripts add up to domainsCovalent Bonds- Depends on how orbitals overlap1. sigma bond= end to end overlap2. pi bond= side to side overlap- To form pi bonds atoms can stretch above/below moleculeDelocalized Bonding- Localized electron = electron with in plane between - Delocalized electron = not between only 2 atomso Sigma electron always localized within planeo Pi electron can localize many ways Compensate for resonance structures by smearing to give extra stability- Steric # = # of outer atoms and # of lone pair electrons on central atomChapter 11Intermolecular Forces and Phase ChangesForces1. Intramolecular- between atoms within moleculea. Strong, influence chemical properties2. Intermolecular- IMF, between atoms of separate moleculesa. Weak, influence physical properties (melting/boiling pt)b. Vander Waal’s forcesTypes of IMF Forces1.London-Dispersion: electron movement causes instantaneous dipole (temporary partial charge)o Present in all compounds (ionic, polar and non-polar)o IMF increase with increase in molecular weight and more linear shape2.Dipole-Dipole- attraction between neutral polar moleculeso Positive end near negative end, stronger than Londono IMF increases with more polar moleculeso High boiling point = high IMF3. Hydrogen bonding- extra strong dipole-dipoleo H bonded with N, O, F4.Ion- dipole- between ions and partial charge of polar molecule o Occur when ionic compounds dissolve in watero Increase IMF with charge of ion and magnitude of dipole- Can have more than 1 force in a moleculeStates of Matter- PE- how molecules are held togethero Charge and distance (IMF)- KE- distance of molecules in containero Speed and temperatureLiquid1. Viscosity- resistance of liquid to flowa. IMF strong/long molecular chain = high viscosityb. High temp decreases viscosity, fast molecules overcome IMF2.Surface tension- energy required to stretch or increase surfacea. Molecule imbalance of IMFi. Interior attracted equally and surface attracted inwardb. Strong IMF = high surface tension3.Capillary Action- rise of liquid through narrow tube against gravitya.