Why do atoms stick together? Chemical Bonding Why do atoms stick together? Who cares?

Types of Bonding Ionic Covalent Metallic Ionic Bonding: Covalent Bonding:

Covalent Bonding Uses Valence Electrons

Also called Lewis Dot Symbols

Lewis Electron-Dot Structures: Describing Bonding in p-block compounds

Interpreting Lewis Structures

Drawing your own Lewis Structures

Wait! Why bother? Lewis Structure Resonance Number of Bonds Molecular Reactivity Lewis Structure Polarity Physical State and Properties Spectroscopy Hydrophilicity and phobicity

Back to Drawing Lewis Structures I have an idea. Do what I say.

Back to Drawing Lewis Structures

Examples

Examples

Examples

Properties of Bonds Polarity Bond Order Bond Length 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 Resonance Formal Charge Oxidation Number Partial Charge

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