1. Functional Groups: are structural features
that show up repeatedly in molecules and seem
to account for some of their chemical properties
(ex: smell).
What are the main functional groups?
O
C
KETONE
(carbon double-bonded to an oxygen)
What are the main functional groups?
O
C
O
C
ESTER
(carbon double-bonded to an oxygen & attached to another
oxygen atom which is attached to another carbon)
What are the main functional groups?
O
C
O H
CARBOXYLIC ACID
(carbon double-bonded to an oxygen & attached to another
oxygen atom which is attached to a hydrogen)
What are the main functional groups?
C
N
AMINE
(carbon bonded to a nitrogen atom)
What are the main functional groups?
ALCOHOL
(carbon bonded to an oxygen bonded
to a hydrogen atom)
What functional group is present in this
molecule?
H
H
H
H
H
H
C
C
C
H
H
C
H
C
H
H
C
H
C
C
H
C
H
H
H
O
H
ketone
C
H
What functional group is present in this
molecule?
H
H
O
C
C
H
O
H
H
C
C
H
H
ester
H
What functional group is present in this
molecule?
O
H
H
H
H
C
C
C
H
C
O
H
H
C
H
H
carboxylic acid
H
What functional group is present in this
molecule?
H
H
H
H
H
H
C
C
C
H
H
C
H
C
H
H
C
H
C
H
C
H
H
C
H
H
H
O
H
Alcohol
C
H
What functional group is present in this
molecule?
H
H
C
N
H
H
H
O
C
C
C
C
C
H
amine
H
H
C
C
H
H
H
4. Structural Formula: A drawing or diagram that
a chemist uses to show how the atoms in a
molecule are connected. It is a 2D picture of
the molecule. Structural formulas show how
the atoms in a molecule are put together. #3
5 (how many?)
on this page shows _____
structural formulas.
5. Molecular Formula: The shorthand notation a
chemist uses to show how many atoms of each
element are present in a particular molecule or
the ratio of ions in an ionic formula. Ex: H2O
6. Bond: A connection between atoms in a
molecule. In structural formulas, the
covalent bonds are represented as
lines
_______________.
Double bond = 2 lines
together. How many lines would you need
3
for a triple bond? ______.
**Question to ponder: Can molecules have the
same molecular formula and smell differently?
Answer: _________
yes
We saw this in the smell lab—2
substances had the formula C4H8O2
but one smelled putrid & the other
smelled sweet!
A. Examine the following molecules. What patterns do you
see in the bonding of hydrogen, oxygen, carbon & nitrogen?
H
H
H
H
H
H
H
H
H
C
C
C
N
C
C
C
H
C
H
H
C
H
H
H
H
H
H
C
H
H
H
C
H
H
H
C
H
C
C
C
H
H
C
H
H
H
O
Vial K—Fishy, diisobutylamine
C
H
C
H
H
H
C
H
H
H
Vial E—Minty, menthone
a. How many bonds (lines) do carbons always
4 b. How about
have around them? ___
3 c. How about hydrogen
nitrogen atoms? ___
1 d. How about oxygen atoms? ___
2
atoms? ___
What do you think the rule
HONC—1234 means?
HONC 1234
H = 1 bond
O = 2 bonds
N = 3 bonds
C = 4 bonds
(H-1) (O-2) (N-3) (C-4)
How it’s done
1. Start with the carbon atoms. Connect them together.
2. Now insert the nitrogen, oxygen, or other atoms.
Remember, they may connect on the ends of the carbon
chain, or somewhere in the middle.
3. Fill in with the hydrogen atoms.
4. Problem-solve until you have the correct number of bonds
for each element.
***Tip: things that can form more bonds are more likely to show
up in the middle of the structure***
You try
D. Draw each of the following molecules:
a. CH4
b. CH4O
c. CH5N
E. Draw C4H10 correctly, but in two different
ways!
Isomer: two or more molecules that are
composed of the same elements in the same
proportions (in other words, they have the
same molecular formula) (ex: C4H10 above)
but differ in properties because of differences
in structural formulas.