Unit 6: Polarity and Intermolecular Forces

bonding is essentially a

tug of war over electrons

If the electronegativities of the two elements are equal (EN <.4-.5), the electrons will be

shared equally (this is a nonpolar covalent bond)

If the electronegativities of the two elements are somewhat unequal (EN .5-.7), the electrons will be

shared unequally (this is a polar covalent bond)

if the electronegativities of the two elements are very unequal (EN >1.7-2.0), the electrons will be

transferred (this is an Ionic bond)

nonpolar bonds

bonding electrons shared equally between 2 atoms (no charges)

polar bonds

bonding electrons shared unequally between 2 atoms (partial charges)

ionic bonds

complete transfer of one or more valence electrons (full charges on resulting ion)

a bond dipole will always point towards

the more electronegative atoms

a bond dipole has both a magnitude and a

direction

if a compound has only nonpolar bonds, it will be a

solid, liquid, or gas

some properties of nonpolar compounds are

soft solid, low melting point, don’t dissolve in water

if a compound has ionic bonds, it will be a

solid (hard)

some properties of ionic compounds are

high melting point, dissolves in water, conducts electricity

if a compound has polar bonds, it could be a solid or liquid, but could also be

a gas

some properties of polar compounds are

dissolve in water, and doesnt conduct electricity

a polar molecule is like a

magnet (it has a positive end and a negative end)