Molecular Polarity

What type of sharing occurs when two atoms of same element form a bond

equal

What type of sharing occurs when two atoms of different elements form a bond

unequal sharing, polar covalent

What is affected by molecular polarity

physical properties (melting and boiling)

What must be present for a molecule to be polar

polar bonds

True or false. Many molecules with polar bonds are nonpolar. Explain why

True because certain arrangements of bond dipoles cancel

Can ions be considered polar/nonpolar, why or why not

neither polar or nonpolar because they are charged

What is an example of a vector

dipoles

What two main properties do vectors have

magnitude (length) and direction

How can vectors (dipoles) cancel

equal length and opposite direction

What can happen to high symmetry molecules with identical polar bonds

cancel

What is the reason nonpolar molecules have polar bonds

reason depends on molecular shape

for diatomics how to find polarity

calculate EN difference

for molecules with more than two atoms, how to find polarity

consider the combined effects of all polar bonds

What is the 1^st step in determining polarity of a molecule

draw structure using proper molecular geometry

Is it possible to determine the polarity of most molecules without drawing the molecule?

no

What is the 2^nd step in determining polarity of a molecule

draw bond dipoles

What is the 3^rd step in determining polarity of a molecule

if bond dipoles cancel, molecule is nonpolar

What is the 4^th step in determining polarity of a molecule

if molecule has uneven dipole distribution, it is polar

Molecules are nonpolar if (3 things)

all electrons around central atoms are bonding pairs

all terminal groups (atoms) are same

the individual bond dipoles cancel

What makes symmetrical molecules nonpolar

because bond dipoles cancel

What makes all five shapes symmetrical

when all domains attached to them are composed of identical atoms

Molecules are polar if (2 things)

all atoms attached to central atom are NOT same

or

there are one or more lone pairs on central atom

What domains do water and ammonia both have, do bond dipoles cancel, and are molecules polar or nonpolar

non bonding domains

bond dipoles don’t cancel

polar