Header image- resonance quiz

Resonance quiz

Answer all the multiple choice questions below to test your knowledge on resonance. Hit the check answer button to get your score when you have completed the quiz.

Chemistry students discussing waht resonance is. Chemistry students explaining what resonance is to other students

1. Which statement best describes a sigma (σ) bond?




2. In an ethene molecule (C2H4), how many sigma (σ) bonds and pi (π) bonds are present between the two carbon atoms in the molecule?

One sigma and one pi bond
Two sigma bonds and no pi bonds

3. Which atomic orbitals can form a sigma (σ) bond through head-on overlap?




4. A pi (π) bond is found in molecules such as ethene and propene and is formed by the sideways overlap of -orbitals. The bond strength of a pi (π) bond compared to sigma (σ) bonds shows that a pi (π) bond is much than a sigma (σ) bond.

5. What is a key characteristic of the electron density in a pi (π) bond?


It allows for free rotation around the bond axis.
It is concentrated above and below the internuclear axis in molecular orbitals
It is typically stronger than a sigma bond.
Image explains that the all the carbon carbon bond lengths in benzene are the same length .

6. What is the meaning of the term "delocalised electrons"?

Electrons that are held firmly in place between two nuclei in a covalent bond

Electrons that are able to move over multiple atoms
Electrons that are only found in simple molecules like methane or water

7. Resonance theory is used to describe molecules where:

All bonding electrons are held firmly between two nuclei
The bonding within a molecule can be accurately represented by a single Lewis structure or molecular diagram showing the position of all the bonding electrons
Nuclei of the atoms involved in bonding are constantly moving
The electrons are delocalised and the bonding cannot be expressed by one single structure

8. Which of the following molecules show resonance?

Methane (CH4)
Carbon dioxide (CO2)
Ethene (C2H4)
Ozone (O3)

9. In resonance structures the move between different contributing forms but the remain in fixed positions and do not move.

10. How many pi (π) electrons are delocalised in a benzene molecule?




Image of a teacher asking the class to explain what resonance is

11. In the circle notation used to represent the benzene molecule what does the circle represent?

The fixed positions of the pi electrons within the ring
The presence of alternating single and double bonds
The delocalisation of the six pi (π) electrons in the benzene ring
The restricted rotation around the carbon-carbon bonds

12. What is the main reason that benzene cannot be accurately drawn using a single structure?

It has too many atoms
Some of its bonding electrons are delocalised
Its bonds are constantly breaking and reforming

13. Why are aromatic amines such as like phenylamine (aniline) poorer bases compared to aliphatic amines?

They are less soluble in water
They generally have more carbon atoms than aliphatic amines
Their nitrogen atom forms fewer bonds in aliphatic amines due to the presence of the benzene ring in aromatic amines
The lone pair of electrons on the nitrogen atom is delocalised into the aromatic ring

14. Which of the following statements is true?

Resonance involves the movement of both electrons and atomic nuclei
The more resonance structures that can be drawn, the less stable a molecule will be.
The overall actual structure of a molecule is a hybrid or composite of all individual resonance structures.
Resonance only occurs in simple molecules like methane

15. Ozone (O3) is a small molecule which undergoes resonance. Which of the following statements is true about the bonding in ozone?

One bond is a single bond and the other is a double covalent bond
Both bonds present between the oxygen atoms are single covalent bonds
Both bonds present between the oxygen atoms are double covalent bonds
Both bonds are identical and intermediate in length between a single and a double bond