Molecular Orbital Theory MO-LCAO:Molecular Orbital-Linear Combination of Atomic Orbitals Lewis Dot Structures don't work for excited states;sometimes they don't even predict the ground state accurately: Example:O2 expected Lewis Dot Structure: Q=9 Actually O2 has two unpaired electrons;this cannot be predicted with Lewis Dot Structures,but it can be predicted with MO-LCAO IX-2Molecular Orbital Theory MO–LCAO: Molecular Orbital–Linear Combination of Atomic Orbitals Lewis Dot Structures don’t work for excited states; sometimes they don’t even predict the ground state accurately: Example: O2 expected Lewis Dot Structure: O O Actually O2 has two unpaired electrons; this cannot be predicted with Lewis Dot Structures, but it can be predicted with MO-LCAO IX-2