BUILD MATTER FROM THE GROUND UP
In Bohr Builder, chemistry isn't something you select from a menu.
You build it yourself.
Aim your particle cannon and fire protons, neutrons, and electrons into a live 2D workspace. Start a nucleus. Change its atomic number. Create isotopes. Fill electron shells. Form ions. Then bring the right pieces together to create chemical products.
Every atom begins with a single particle—and every particle has to get there.
AIM. FIRE. BUILD AN ATOM.
Bohr Builder turns atomic structure into a hands-on physics game.
Protons and neutrons must reach the nucleus. Electrons have to be captured into their Bohr shells. Particles move through the workspace, interact with atoms, and can bounce away when your aim is off.
Launch speed is fixed, so success comes down to where you aim and how well you understand what you're building.
A proton changes the element.
A neutron changes the isotope.
An electron changes the charge.
Simple rules gradually become surprisingly intricate constructions.
CONSTRUCT ALL 118 ELEMENTS
Build your way across the periodic table, from hydrogen all the way to oganesson.
Bohr Builder tracks the actual particle counts inside your creations, allowing you to construct elements, isotopes, and monatomic ions from their constituent particles.
Inspect anything you've made to see its element, atomic number, proton count, neutron count, electron count, mass number, and electrical charge.
The difference between two species isn't an arbitrary game rule. It's visible in the atom you constructed.
A 200 LEVEL CAMPAIGN
The campaign starts with the fundamentals and steadily removes the training wheels.
The first 50 levels focus on neutral atoms and molecular products, teaching you how different elements and isotopes are assembled.
From Level 51 onward, ions enter the equation.
Now electron counts matter just as much as nuclei, and you'll need to construct positively and negatively charged species in the correct ratios to produce charge-balanced ionic compounds.
As the campaign progresses, assistance decreases and the constructions become larger and more demanding.
CHOOSE HOW MUCH HELP YOU WANT
Play the campaign in two different ways.
Guided Mode gives you chemical names, equations, lessons, and exact construction requirements. It's ideal for learning how the systems work or getting comfortable with unfamiliar chemistry.
Formula Only Mode strips that information away.
You get the formula.
You work out the rest.
What elements are required? How many of each? Should they be neutral or charged? How many protons, neutrons, and electrons does each species need?
The underlying challenge is identical. The difference is how much chemistry you have to solve yourself.
EXPERIMENT IN FREEPLAY
Don't want a target?
Open Freeplay and build whatever you like.
Create arbitrary atoms and ions, inspect their properties, remove experiments you no longer need, and assemble your own collection of species across the workspace.
When you've created something interesting, select multiple species as reactants and attempt to combine them.
Bohr Builder includes an offline library of recognised chemical products, letting you experiment with molecular and ionic compounds outside the campaign.
Freeplay turns the game into an interactive atomic construction set: part sandbox, part chemistry puzzle, and part physics toy.
LEARN BY DOING
Bohr Builder isn't about memorising a periodic table and answering a multiple-choice question afterwards.
The chemistry is the interaction.
To create carbon, you need to understand what makes carbon carbon.
To create an isotope, you need to understand what changed.
To create an ion, you need to understand where its charge comes from.
And to build a compound, you first have to construct the individual pieces that make it possible.
Whether you're already comfortable with chemistry or you're discovering atomic structure for the first time, Bohr Builder gives you something a textbook can't:
The chance to pick up the particles and build it yourself.
FEATURES
• Construct atoms by physically firing protons, neutrons, and electrons
• All 118 recognised elements
• Build and inspect different isotopes
• Create positively and negatively charged monatomic ions
• 200-level chemistry campaign
• Neutral chemistry progressing into charge-balanced ionic compounds
• Guided campaign mode with lessons, equations, and requirements
• Formula Only mode for a more demanding chemistry challenge
• Open-ended Freeplay sandbox
• Select constructed species and attempt chemical reactions
• Offline library of recognised molecular and ionic products
• Simplified Bohr shell electron visualisation
• Particle physics with aiming, capture, attraction, and repulsion
• Persistent campaign progression
• Mouse and keyboard support
• Full controller support
Pick a particle. Take aim. Build matter.
