ionic bond
electrostatic attraction between positive and negative ions
transfer of electrons
from metal to nonmetal
strength of ionic bonds
smaller ions = stronger bond
greater magnitude of charge = stronger bond
polar covalent bonds
difference in EN
unequal sharing of electrons, dipoles
between 2 different nonmetals
nonpolar covalent bonds
no difference in EN
equal sharing of electrons, no dipoles
between 2 of the same nonmetal or when the difference in EN is 0.4 or below
VSPER theory
Valence Shell Electron Pair Repulsion
electron domains around the central atom repel and get as far apart as possible
2 bonding domains, 0 nonbonding domains
linear, linear (180 degrees)
3 bonding domains, 0 nonbonding domains
trigonal planar, trigonal planar (120 degrees)
2 bonding domains, 1 nonbonding domains
trigonal planar, bent (118 degrees)
4 bonding domains, 0 nonbonding domains
tetrahedral, tetrahedral (109 degrees)
3 bonding domains, 1 nonbonding domains
tetrahedral, trigonal pyramidal (107 degrees)
2 bonding domains, 2 nonbonding domains
tetrahedral, bent (105 degrees)
bond polarity
in an individual bond, one side is more negative than the other
molecule polarity
the polarity of the molecule as a whole taking into account:
bond polarities
the shape of the molecule
there are dipoles in the molecule and the bond dipoles don’t cancel
polar molecule
there are dipoles in the molecule and the bond dipoles do cancel
nonpolar molecule
there are no dipoles in the molecule
nonpolar molecule
polar molecules IMFs
hydrogen bonding (if H + N,O,F)
dipole-dipole forces (not hydrogen bonding)
nonpolar molecules IMFS
london dispersion forces
lower strength IMFs
high evaporation rates, low boiling/melting point, easy to go from solid-liquid-gas
higher strength IMFs
low evaporation rates, high boiling/melting point, hard to go from solid-liquid-gas
why hydrogen bonds are strong
H,N,O,F are all very small atoms
big difference in EN between H and N,O,F
affecting the strength of LDFs
lots of electrons = strong LDF
shape of molecule