Properties of Bonds

1.Polarity2.Bond Order3.Bond Length4.Bond Energy

Electronegativity Bond Polarity

Electronegativity: ability of a bonded atom to attract the shared electrons towards itself

Origin: Orbital Energies

Trends:

Continuum from Covalent to Ionic Bonding: Bond Character

Bond Order: # of bonds between two atoms

Bond Length

Bond Energy: Energy to separate two bonded atoms

Bond Energy in Ionic Compounds: Lattice Energy

Energy to separate all the ions

NaCl(s) Na+(g) + Cl-(g) H = Lattice E = -790 kJ/mol

Properties inside Molecules

1.Resonance2.Formal Charge3.Oxidation Number4.Partial Charge

Resonance and Bond Order

Resonance Structures:

When more than one reasonable Lewis Structure is possible

Formal Charge and Oxidation Number Examples

Partial Charge

Lewis # Structural Electron Molecular Structure Pairs Geometry Geometry

# Structural Pairs = # bonded + # lone on central atom atoms pairs

# Structural Pairs determines Electron Pair Geometry

# Structural Pairs determines Electron Pair Geometry

# Structural Pairs determines Electron Pair Geometry

Molecular Geometry = Electron Pair Geometry, ignoring lone pairs

BF3 and O3

Molecular Geometry = Electron Pair Geometry, ignoring lone pairs

Molecular Geometry = Electron Pair Geometry, ignoring lone pairs

Molecular Geometry = Electron Pair Geometry, ignoring lone pairs