CHEM STUDY GUIDEElecton Domain Geometry- includes lone pair electronsMolecular Geometry- excludes lone pair electronsLattice Energy- Higher LE=lower charge, increases up the table. Lower LE=higher charges, in decreases down tableEmpirical Formula= addition of all elements then ratio is simplifiedMolecular Formula= number of every elementStructural isomers have the same molecular formula but different structural formulas - the connectivity of the atoms is different Geometric isomers have the same molecular formula and the same structural formula, but have different spatial arrangements.Hybridization- # of electron domains (1 double bond, 1 single bond, 1 lone pair= sp2)Sigma and pi bonds- single bond=1 sigma, double bond=1 sigma&1 pi, triple bond= 1 sigma&2 piIonic- difference in electronegativity of 1.7 or moreLondon Dispersion Forces- Molecule is symmetrical and dipole forces cancel out (H2, CH4)Dipole Dipole- Difference in electronegativity less than 1.7 creating permanent dipoles. Also occurs when there is asymmetry. (If uneven lone pairs exist, its dipole-dipole)Hydrogen bonding- similar to dipole-dipole, but occurs when hydrogen bonds to Nitrogen, Oxygen, or Fluorine. (Hydrogen bonding is “FON”)ALL MOLECULES HAVE LDFDelocalized pi bonds means the molecule contains resonance structuresBoiling point increases as the length of the carbon chain increases. This is because London dispersion forces increase with chain length (for alkanes)Alkanes= CnH2n+2 so possible alkenes =CnH2n, and alkynes= CnHn-xFor greatest dipole moment, look for largest difference in EN.For determining most stable Lewis Structure, look at the formal charge. The most EN element should have a FC of
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