IntramolecularIntermolecular

Types of Bonding

Definitions

Bond: a type of interaction between atoms that result in atoms staying close together

Molecule: two or more atoms held together by a covalent bond

Intramolecular: forces of attraction within a molecule (e.g. intramurals)

Intermolecular: forces of attraction between molecules in a compound (e.g. international)

Types of Interactions Summary

Intermolecular

Intramolecular

Intramolecular Bonds

Electronegativity: attraction of an atom for electrons

Example of a very electronegative atom: oxygen

When two atoms with different electronegativity get together…

Intramolecular Bonds

Intramolecular: Ionic

If two atoms with very large differences in electronegativity get together, one of atom could take away an electron from the other

Acceptor “stealer” of electron becomes negativity charged (anion = negative ion)

Donor of electron becomes positively charged (cation = positive ion)

Intramolecular: Ionic

Ionic bond forms from an attraction between an anion and cation

Ionic compounds are formed by ionic bonds

Salts are ionic compounds (e.g. Na+ + Cl- NaCl)

Salt crystals have a 3D lattice because of +/-attractions

Types of Interactions Summary

Intermolecular

Intramolecular

Covalent Ionic

Intramolecular: Covalent

Covalent bond forms when atoms share electrons

Nonpolar covalent bond atoms have the same electronegativity electrons are equally shared e.g. H2

Polar covalent bond atoms have slight differences in

electronegativity electrons are unequally shared e.g. HCl

Polar Covalent Bond

Polarity of a Molecule

BondShape Nonpolar bond Polar bond

Symmetrical

nonpolar molecule(e.g. H2)

nonpolar molecule(e.g. CO2)

Assymetrical

nonpolar molecule

polar molecule(e.g. HCl, H2O)

Polarity dependent on the polarity of the bond AND the molecular SHAPE

Polar Covalent Bond

Polarity

Ionic Versus Molecular

Types of Interactions Summary

Intermolecular

Intramolecular

Nonpolar Covalent

Covalent Ionic

Polar Covalent

Intermolecular Forces

Types of Interactions Summary

Intermolecular

Intramolecular

Nonpolar Covalent

Covalent Ionic

Polar Covalent

London (dispersion)

forces

Dipole-dipole Hydrogen bonding &Ion-dipole

London Dispersion

Exists between all molecules

Weak force, due to instantaneous diploes

Dipole-Dipole

Exists between polar molecules

Due to permanent dipoles

Hydrogen Bonding

Strong force (just a very strong dipole-dipole)

Between a polar molecule with an H-atom and a polar molecule with an electronegative atom (usually O, N or F)

Ion-DipoleIon-Dipole

Dipole is attracted to an oppositely charged ion

When ionic compounds dissolve in water, water molecules surround the ion and remove it from the crystal lattice structure (hydration shell)

Hydrophobic Interactions

Nonpolar molecules are excluded from mixing with polar molecules

Nonpolar molecules tend to associate with each other

Can occur spontaneously (e.g. oil molecules spontaneously associate excluding water)