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Bondingo!

Created: 2026-02-09

Author(s):
Floor Stikkelbroeck (NanoSpace), Chris Ewels (NanoSpace)

How do atoms bond together to form molecules? In this activity, students play together to build molecules using hydrogen, oxygen, and carbon, exploring the basic concepts of bond formation through direct physical representation. No complex terminology is needed: students intuitively learn about chemical bonding by acting as atoms themselves, with their hands—or simple pen-and-paper drawings—representing the bonds between them.
The activity begins with simple molecular structures, such as hydrogen (H₂) and oxygen (O₂), and progresses to slightly more complex cases like ozone (O₃). By combining different atoms, students observe how molecular structure affects stability, comparing examples such as water and hydrogen peroxide. Introducing carbon, with its four possible bonds, allows students to build more complex molecules, including ring structures like benzene and repeating patterns that resemble graphene.

This activity has been developed as part of the NanoSpace COST Action.

Materials

Power point presentation (see attachments in pdf)
OPTIONAL: Pen & Paper

Goals

Students will:

Have fun with chemistry
Have a hands-on experience with atoms

Learning Objectives

Students will:

understand the bonding rules of hydrogen, oxygen, and carbon, and how many bonds each atom can form
build and recognise simple and complex molecules, including symmetrical structures.
connect molecular structures to real-world examples such as water, ozone, and polymers.
develop an intuitive, accessible understanding of chemical bonding without advanced terminology.

Background

Atoms bond with each other because they want to reach a “full set” of electrons in their outer shell. Electrons are the tiny negatively charged particles that move around the nucleus of an atom, and atoms are most stable when this outer shell is filled. To do this, atoms share electrons with other atoms, creating covalent bonds.

Different atoms have different numbers of “spaces” in their outer shell, which is why they can only make a certain number of bonds:

Hydrogen (H): Has only 1 electron and needs 1 more to fill its shell. That means hydrogen can make 1 bond only. Two hydrogens share their single hands and form H2.
Oxygen (O): Has 6 electrons in its outer shell but needs 8 to be full. It can share 2 electrons with other atoms, so oxygen makes 2 bonds. Two oxygens make O2 by sharing two pairs of electrons (a “double bond”). Adding a third oxygen forms O3 (ozone), but the extra oxygen makes the molecule less stable.
Carbon (C): Has 4 electrons in its outer shell and needs 8. This means carbon can share with 4 different atoms, giving it 4 bonds. This flexibility allows carbon to make a huge variety of molecules: from the simple methane molecule (CH₄) to long chains, rings like benzene, and even giant structures like graphene.

Image: a representation of H, O and C atoms

A molecule is stable only if all the bonding “slots” (the empty spaces in the outer shell) are filled. That’s why H2O works perfectly, oxygen’s two bonds connect to two hydrogens. Similarly, O2 is the common form of oxygen we breathe, while O3 (ozone) exists but is fragile and breaks apart easily.

This simple rule, hydrogen 1, oxygen 2, carbon 4, explains most of the molecules we see in the world around us. Water is vital for all living things, oxygen sustains life on Earth, ozone protects us from harmful solar radiation, and carbon compounds are found in fuels, plastics, and even cutting-edge technologies.

In astronomy, these same molecules are equally important. Water vapour, ozone, carbon dioxide, and methane are detected in the atmospheres of planets and moons, and astronomers use them to study climate and the potential for life. In space between the stars, large carbon molecules such as benzene and fullerene (C60) have been discovered. Understanding chemical bonding helps explain how these molecules form and survive in extreme cosmic environments, and why they are crucial clues in the search for life beyond Earth.

Further reading:
https://www.youtube.com/watch?v=NgD9yHSJ29I&t=1s

https://www.khanacademy.org/science/ap-biology/chemistry-of-life/introduction-to-biological-macromolecules/a/chemical-bonds-article

Full Description

NOTE: When introducing this activity, it helps to start with simple, accessible language before moving to formal scientific terms. For example, you can say that atoms are “happy” when their hands are joined (bonded), and “unhappy” when they are alone (unbound or radicals). If a bond is energetically favourable, you can explain it as the atom “wanting to bond.” To make the idea of atoms less abstract, invite students to imagine that you have a big bag of balls representing atoms, which you can take out and stick together. Their hands and arms represent the available bonds. For hydrogen, have one hand behind their back or in a pocket to show that it only has one bond. As students become more confident, you can gradually introduce the proper scientific terms such as “bond,” “radical,” or “energetically favourable.”

Preparation:

Decide whether students will represent atoms themselves (using their hands as bonds) or use pen & paper to represent atoms and organize the classroom consequently.
Review the bonding rules with the class: hydrogen = 1 bond, oxygen = 2 bonds, carbon = 4 bonds. Demonstrate with a few examples
ATTENTION: Slides are optional and the advice is to to show them only after the game is played, to reveal solutions. Showing them beforehand may spoil the discovery process.

Tutorial Mode (working through examples together):

Give each student or group 6 carbons and 6 hydrogen to work with (Optional: use the powerpoint)
Work through the following examples:

H only → only H2 possible.
O only → O2 (stable), O3 (less stable, “not so happy”).
H + O → H2O (stable), H2O2 (bonus/easter egg).
Main challenge = 6C + 6H, but you can also leave this for the Game Activity

Explain why this sequence is important: builds rules step by step.

NOTE: if the students use their hands and feet, tell for the hydrogen atom to put one or their hands behind their back or in their pocket.

Game Activity Steps (During the Activity):

Divide the class into teams (2–3 students per team works well). Give each team their “atoms.”
Explain the challenge: Teams must build as many valid molecules as possible within the time limit (10–15 minutes is recommended).
Building molecules: Students connect atoms by holding hands or writing them on pen & paper. Every atom must have the correct number of bonds to form a valid structure.
Scoring system:
1 point: Simple molecules (H₂, O₂, CO₂, CH₄, etc.)
2 points: Slightly larger molecules (H₂O₂, C₂H₆, etc.)
3 points: Ring structures (benzene, cyclohexane, etc.)
Bonus point: If the team can correctly name the molecule or connect it to an everyday example (e.g. “H₂O is water we drink”).
Keep track of points on the board as teams present their molecules. Molecules must be “checked” by the teacher (or another team) to confirm validity before points are awarded, and two teams cannot have the same molecule, the first one wins the point.
Wrap-up discussion: Highlight the enormous variety of molecules, even with a few atoms (graph theory shows ~600 possibilities for 6 carbons and 6 hydrogens. Connect this to the richness of chemistry and its importance in everyday life and astronomy. Optional: do the evaluation with the students.

Image: some of the molecules that can be built in Bondingo

Teacher Tips:

Give students clues: look for symmetry, try smaller substructures (2C + 2H) and repeat.
Mention molecules are 3D if bonds cross on paper.
If all carbons have 4 bonds to other carbon you can link to diamonds.
Encourage competitive play with team names and points on a whiteboard.

Evaluation

Possible questions to ask the students for evaluation:

How many bonds (“hands”) can a hydrogen, oxygen, and carbon atom each form?
(answers: H = 1, O=2, C=4)
Can you draw or act out how water (H2O) is built from hydrogen and oxygen atoms?
What is one example of a molecule with a symmetrical structure?
(answers: Water, Benzene)
Which molecules that you built today also exist in everyday life (e.g. in water, the atmosphere, or materials)?
(answers: water, carbondioxide)
In your own words, how does the “hands and atoms” game help explain chemical bonding?

Educational Activity

Originally developed in

Netherlands

Keywords

chemistry atmosphere molecule chemical bond