Day 1
WYATT’S ORGANIC WORKSHOP
TM
ANSWERS to Optional Practice Problems:
For the following molecules:
a. Draw the Lewis Structure (remember what this means).
b. Determine if the bonds in the structure are non-polar covalent, polar covalent, or ionic.
c. If the structure contains only covalent bonds then determine what intermolecular forces
is possesses.
d. If the structure is ionic (remember what typically makes this true) draw it as an ionic
structure.
e. Calculate the formal charge for all the atoms in the structure.
NOTE: THE ANSWERS TO “b” IS ONLY BASED ON ELECTRONEGATIVITY VALUES.
1. CH3CH2NH2
a.
H H H
H C1 C 2 N H
H
H
c. Structure has London Dispersion, Dipole-Dipole,
and H-Bonding intermolecular forces.
d. NA
b. ! C-H bonds are non-polar covalent
! C1 -C2 bond is non-polar covalent
! C 2-N bond is polar covalent
! N-H bonds are polar covalent
e. FC = Atoms Valence Electrons - Electrons it owns
FC
FC
FC
FC
for all H's = 1 - 1 = 0
for C1 = 4 - 4 = 0
for C 2 = 4 - 4 = 0
for N = 5 - 5 = 0
2. KSCH3
a. K
S
H
C H
H
b. K S bond is ionic
! S-C bond is polar covalent
! C-H all are non-polar covalent
c. NA
d. K
SCH3
e. FC = Atoms Valence Electrons - Electrons it owns
FC
FC
FC
FC
for all H's = 1 - 1 = 0
for C = 4 - 4 = 0
for S = 6 - 7 = -1
for K = 1 - 0 = +1
Day 1
WYATT’S ORGANIC WORKSHOP
TM
3. CH3CHClCHO
a.
H
H C1
H
O
Cl
C2 C3
H
H
b. ! C1-C2 bond is non-polar covalent
! C2-C3 bond is non-polar covalent
! C2-Cl bond is polar covalent
! C-H all are non-polar covalent
!/" C3-O bond is polar covalent
c. Structure has London Dispersion, and Dipole-Dipole
intermolecular forces.
d. NA
e. FC = Atoms Valence Electrons - Electrons it owns
FC for all H's = 1 - 1 = 0
FC for C1 = 4 - 4 = 0
FC for C2 = 4 - 4 = 0
FC for C3 = 4 - 4 = 0
FC for Cl = 7 - 7 = 0
FC for O = 6 - 6 = 0