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CHAPTER 5:THEORY OF CHEMICAL BONDING - Coggle Diagram
CHAPTER 5:THEORY OF CHEMICAL BONDING
5.1 VALANCE BOND THEORY
ATOMMIC ORBITAL OVERLAP
A COVALENT BOND IS FORMED BY THE PAIRING OF TWO ELECTRONS WITH OPPOSING SPINS IN THE REGION OF OVERLAP OF ATOMIC ORBITALS BETWEEN TWO ATOMS
Pi BONDS
SIDE-TO-SIDE OVERLAP
ELECTRON DENSITY ABOVE AND BELOW THE INTERNUCLEAR AXIS
SIGMA BOND
HEAD ON OVERLAPPING OF ONE P WITH ANOTHER P ORBITAL
OVERLAP OF ONE S ORBITAL WITH ANOTHER S ORBITAL
OVERLAP OF ONE S ORBITAL WITH A P ORBITAL
5.2 MOLECULAR ORBITAL THEORY
ORBITAL MIXING:COMBINATION OF ATOMIC ORBITALS
BE CLOSE TOGETHER
HAVE SIMILIAR ENERGY LEVELS
OVERLAP WELL(SIMILIAR ORIENTATION)
BOND ORDER
AS THE BOND ORDER INCREASES,THE BOND ENERGY INCREASES AND THE BOND LENGTH DECREASES
LARGE BOND ENERGY ASSOCIATED WITH N2 MOLECULE,WHICH THE MOT MODEL PREDICTS WILL HAVE A BOND ORDER OF 3,A TRIPLE BOND
PARAMAGNETISM
SUBSTANCE ATTRACTED INTO A MAGNETIC FIELD
DIAMAGNETISM
SUBSTANCE REPELLED INTO A MAGNETIC FIELD
PROBLEMS WITH THE LOCALIZED ELECTRON MODEL
DOES NOT DEAL EFFECTIVELY WITH MOLECULES CONTAINING UNPAIRED ELECTRONS
GIVE NO DIRECT INFORMATION ABOUT BONDING ENERGIES
INCORRECTLY ASSUMES THAT ELECTRON ARE LOCALIZED AND CONCEPT OF RESONANCE MUST BE ADDED
5.3 VALANCE SHELL ELECTRON PAIR REPULSION THEORY
ELECTRON-GROUP GEOMETRY
THE REPULSIONS AMONG ELECTRON GROUPS LEAD TO AN ORIENTATION OF THE GROUPS
THE EFFECT OF NONBONDING ELECTRON
BOND ANGLE DECREASES WHEN THE NUMBER OF LONE PAIRS INCREASES
LONE PAIR-LONE PAIR REPULSION>LONE PAIR-BOND PAIR REPULSION>BOND PAIR-BOND PAIR REPULSION
MULTIPLE BONDS AND BONDS ANGLES
DOUBLR AND TRIPLE BONDS PLACE GREATER ELECTRON DENSITY ON ONE SIDE OF THE CENTRAL ATOM THAN DO SINGLE BOND
THEY ALSO AFFECT BOND ANGLES
MOLECULAR GEOMETRY
MOLECULE POLRITY AND MOLECULAR SHAPE
IT IS POSSIBLE FOR A MOLECULE TO CONTAIN POLAR BOND,BUT NOT IN POLAR
IN WATER,THE MOLECULE IS NOT LINEAR,AND THE BOND DIPOLES DO NOT CANCEL EACH OTHER
5.4 HYBRID ORBITAL THEORY
HYBRID ORBITALS
MORE ENERGY IS SUPPLIED FOR THIS PROMOTION FROM THE FORMATION OF TWO ADDITIONAL COVALENT BOND
CHROLINE FORMS ONE BOND AND HAS ONE UNPAIRED ELECTRON
OXYGEN,WITH TWO UNPAIRED ELECTRONS,USUALLY FORMS FOUR BONDS
AN ELECTRON FROM THE 2s ORBITAL IS PROMOTED TO THE VACANT 2p ORBITAL
HYBRIDIZATION OF ATOMIC ORBITALS
A 2s ELECTRON IS PROMOTED TO AN EMPTY 2p ORBITAL,THEN FOUR UNPAIRED ELECTRONS CAN GIVE RISE TO FOUR BONDS
BONDING IN METHANE
EACH OF THE FOUR C-H BONDS RESULTS FROM HEAD-ON OVERLAP OF A SINGLY OCCUPIED CARBON sp3 HYBRID ORBITAL WITH A SINGLY OCCUPIED HYDROGEN 1s ORBITAL.
sp2 HYBRIDIZATION
COMPRISED OF ONE 2s ORBITAL AND TWO 2p ORBITALS TO PRODUCE A SET OF THREE sp2 HYBRID ORBITALS