Atom Builder

Build from the ground up: quarks into nucleons, nucleons into atomic nuclei, atoms into molecules.

1Quarks & Gluons

Protons and neutrons aren't elementary particles — each one is made of three quarks, held together by gluons (the gauge bosons of the strong force).

Structure
u u d
Proton — charge +1
u d d
Neutron — charge 0
Yellow lines = gluons
u = up quark (+²⁄₃)
d = down quark (−¹⁄₃)
Charge: —
Add three quarks …
Inventory No nucleons created yet.
▼   Add nucleons to atomic nuclei

2Atomic Nuclei

Protons and neutrons from your inventory bind together via the strong nuclear force to form atomic nuclei. Fuse a nucleus to place the atom into your inventory.

Nucleons Build nucleons in step 1 first.
1 Protons
0 Neutrons
Presets
Proton
Neutron
1 1
H
Hydrogen
Protium ¹H
1
Z Protons
0
N Neutrons
1
A Mass
Stable
The only stable isotope without neutrons.
Consumes: 1 proton, 0 neutrons
Atom inventory No atoms fused yet.
▼   Combine atoms into molecules

3Molecules

Combine atoms from your inventory into molecules. Green ingredients are available, red ones are still missing.

Atom inventory Fuse atoms in step 2 first.