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Atom Builder

Build atoms by adding protons, neutrons, and electrons. Select an element from the periodic table below to get started, then use the controls to construct the atom step by step.

How to Use the Atom Builder:

  1. Select an element from the periodic table
  2. Add protons to match the element's atomic number
  3. Add neutrons (try the common isotope mass shown)
  4. Add electrons (same as protons for neutral atoms)
  5. Place electrons in shells or orbitals using the placement area
  6. Watch the real-time feedback to build the perfect atom!
Element Selection

Select an Element

Click on any element to start building that atom

s-block
p-block
d-block
f-block
Atom Builder Canvas
Protons
0
Neutrons
0
Electrons
0
Mass Number0
P + N
Charge0
P - E

Electron Shells

Electrons to place: 0
How to Use:
  • Drag blue electrons to shells
  • Click shell electrons to remove
  • Shells auto-validate capacity
  • Toggle animation with button
Electron Status
AnimationRunning
Electrons are orbiting
Free Electrons: 0
All electrons are placed in shells
Shell Status:
Shell 10/2
2 spaces available
Shell 20/8
8 spaces available
Shell 30/18
18 spaces available
Shell 40/32
32 spaces available
Quick Actions: