COVALENT BONDS

• Covalent bonds - formed when two atoms share one or more pairs of electrons to fill their valence shell
• Bonding valence electrons are attracted by both nuclei in the bond.
• Bond length depends on the nature of the atoms bonded and the number of electrons participating in the bond.
• Carbon-carbon double bonds are generally longer and have less bond energy than do carbon-carbon triple bonds.
• Atoms are held together by these
• Strength and bond length depends on: Nature of atoms bonded Number of e- pairs shared
• Greater number of pairs, greater bond energy, lower bond length

INTERMOLECULAR FORCES

• Non-covalent interactions
• Electrostatic interactions
• Ionic interactions
• Non-ionic interactions (electrically neutral)
• Fixed dipole-dipole
• Hydrogen bonds, electronegative
• Fixed dipole-induced dipole
• Induced dipole- induced dipole (london dispersion forces, van der Waals Forces)