CHEM STUDY GUIDE Electon Domain Geometry includes lone pair electrons Molecular Geometry excludes lone pair electrons Lattice Energy Higher LE lower charge increases up the table Lower LE higher charges in decreases down table Empirical Formula addition of all elements then ratio is simplified Molecular Formula number of every element Structural 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 pi Ionic difference in electronegativity of 1 7 or more London 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 LDF Delocalized pi bonds means the molecule contains resonance structures Boiling 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 x For 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 zero
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