Unit 9: Advanced Bonding Theory

Bond length or bond distance - the distance between the nuclei in a bond

Covalent Radii - values assigned to atoms such that the sum of the radii of atoms “A” and “B” approximate the A-B bond length

Bond Order - the number of pairs of electrons in a bond

Bond length depends on - bond order

As bond order increases, the bond gets - shorter and stronger

Bond Energy - the average enthalpy change for breaking an A-B bond in a molecule in its gas phase

Valence bond theory - to explain the covalent bond from a quantum mechanical view

What two conditions need to be met for a bond to form between two atoms? - Two atomic orbitals “overlap”, the total number of electrons in both orbitals is less then or equal to 2

Hybrid orbitals - bonding orbitals obtained by combinations of atomic orbitals of an atom

Hybridization for linear geometric arrangement - sp

Hybridization for trigonal planar geometric arrangement - sp2

Hybridization for tetrahedral geometric arrangement - sp3

Hybridization for trigonal bipyramidal geometric arrangement - sp3d

Hybridization for octahedral geometric arrangement - sp3d2

σ bonds - overlap along bonding axis

π bonds - off bonding axis overlap, “side to side”, 2 places of overlap

Constructive [molecular orbital theory] - bonding

Destructive [molecular orbital theory] - antibonding

Molecular orbitals [molecular orbital theory] - spreading over several atoms or entire molecule