SNC1D – Chemistry
Name: _____________________
BUILDING MODELS OF MOLECULES
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A molecule is a combination of two or more atoms.
These atoms are held together by bonds.
The bonds represent the electrons of the atoms.
We draw the bonds of atoms using structural diagrams.
A structural diagram represents a molecule with chemical symbols for atoms and lines for
the bonds.
 You must know the number of bonds in selected atoms so you can draw or build the
molecule. Know this!
 However, molecules may contain a
different number of atoms & this will
change the number of bonds that is
present.
Water (H2O) has 2 hydrogen
& 1 oxygen atom.
H
O
H
Structural diagram
# of connections
per atom
Atom
Hydrogen
Oxygen
Nitrogen
Carbon
one
two
three
four
Hydrogen peroxide (H2O2)
has 2 hydrogen & 2 oxygen
atoms.
H
O
O
H
Structural diagram
Below are examples of ball and stick diagrams (all ball and stick diagrams can be written as
structural diagrams).
SNC1D – Chemistry
Name: _____________________
Building Models
You must know the number of bonds in the
atoms so you can build molecules.
All bonds must be used up for each atom. No
bonds can be left undone.
Water: H – O – H
Model
Atom
Colour
Hydrogen
# of bonds
per atom
Oxygen
Nitrogen
Carbon
Build each model below.
Check it with the teacher, and then draw the ball and stick diagram for each one in the space provided. Use the correct
colours on your drawings. If you finish all of the molecules try to create a glucose molecule (C6H12O6).
Ammonia (NH3)
Ethane (C2H6)
Oxygen gas (O2)
Nitrogen gas (N2)
Carbon dioxide (CO2)
Methanol (CH3OH)
Formaldehyde (HCHO)
Ethanol (C2H5OH)
Ethylene (C2H4)
Acetic Acid – vinegar (CH3COOH)