Covalent Builder — Dots & Crosses
Place the electrons so every atom has a full outer shell.
? How to use
Guided
Test
1. Difficulty
Easy
Medium (includes Easy)
Hard (includes Easy & Medium)
2. Clicking will…
+ Add
− Remove
3. Check
Check
Show answer
Clear
New random
How to use
Press
New random
to get a molecule.
Click the
overlap
between two atoms to add a shared (bonding) electron. Click
inside one atom
to add a lone-pair electron.
Use
Remove
mode (or hold
Shift
) to take an electron away.
Press
Check
. Use
Show answer
only after trying.
Key
Dot electron
Cross electron
Overlap: shared electrons go here
8/8
Electrons around the atom / needed (turns green when full)
Got it