Bond length, Strength and Order Activity
Name: _____________________. Group members: __________________________________
Using molymods is a way to model the interactions between atoms. Models are useful because they allow us
to “see” an idea, but they also have limitations.
In this activity, you will be investigating the strength and length of the different bonds (single, double, and
triple) between carbon atoms.
Bond order is the number of bonding pairs of electrons between two atoms. In a covalent compound,
a single bond has a bond order of one, a double bond has a bond order of two, a triple bond has a bond
order of three, and so on.
Bond length is the distance between the nuclei in a covalent bond.
Create a hypothesis about the relationship between bond length and strength in the box below:
PART 1:
Using the molymods, ONE BY ONE, make each of the compounds in the table.
- Count the number of bonds between the two atoms
- State the bond order
- Measure the length of the bond from the center of the atom to the center of the atom it is
bonded to. This is known as the bond length
- Draw the corresponding Lewis structure. (do not worry about whether the outer shell is full or
not)
- For each compound, try to pull them apart using just you finger and thumb on each hand
Compound
Carbon with
single bond
Carbon with
double bond
Carbon with
triple bond
Oxygen with
single bond
Oxygen with
double bond
Nitrogen with
single bond
Nitrogen with
double bond
Nitrogen with
triple bond
Number of
bonds
Bond order
Length of
bonds
Lewis structure
Difficulty to
separate
1. What do you observe as the number of bonds changes?
2. What do you think that means in terms of bond strength?
3. Why was it impossible to make nitrogen with a triple bond?
4. Describe the limitations of the model.
5. CHALLENGE QUESTION: What happens to the radius of atoms as the number of bonds increases?
PART 2:
The energy input required to break a bond is known as bond energy.
Using the toothpicks provided:
- Start with one toothpick and break it. Then break it again. And repeat until you can’t do it
anymore.
1. What does the smaller and smaller pieces of toothpick represent?
-
Repeat the toothpick breaking again, but this time with TWO toothpicks.
Repeat the toothpick breaking again, but this time with THREE toothpicks.
2. From your observations, put each of the bond types (single, double, triple) in increasing order for
a. Bond length
b. Bond strength
c. Bond energy
In the box below, write you new theory about the bond length, strength and bond energy.
CHALLENGE: Using the models, make HCN. Identify the types of bonds. How could you calculate the
bond order as there are more than two atoms….?