Molecular Polarity and Intermolecular Forces

electronegativity

the ability of an atom to attract a shared electrons within a covalent bond

nonpolar covalent bonding

llectrons are shared equally → atoms have same electronegativity

polar covalent bonding

electrons are shared unequally → atoms have different electronegativities → electrons attracted more closely to atoms with the higher electronegativity

ionic bonding

electrons transferred

bond polarity

the distribution of electric charge across a chemical bond between two atoms

Van Der Waals forces

• attraction between temporary dipoles

• exists in all molecules both polar and non-polar

• caused by the electrons of one molecule being attracted to the nucleus of another molecule; forming temporary (instantaneous) induced dipoles.

• the more electrons a molecule has (from larger atoms / bigger atoms), the stronger its VDW forces because there is a more prominent temporary dipole

dipole-dipole forces

• attraction between permanent dipoles

• occurs in all polar molecules

• caused by the attraction of the partial positive end  (δ+) of one molecule to the partial negative end (δ-) of another molecule, and vice-versa

hydrogen bonding

• attraction between permanent dipoles: F-H, O-H, N-H (FON)

• special type of dipole-dipole force that is very strong

• caused by the attraction of hydrogen atoms bonded to F, O, N (high EN) in one molecule to the lone pair of electrons on the F, O, N atom of another molecule