Who's building today?

Your progress is saved on this device, so typing the same name again will pick up right where you left off.

Electrons, shells & bonding

Every element shows its real electron shells. The dashed amber ring is the valence shell — only those electrons bond.

• Tap an element below to add it to the workspace.
• Drag two atoms together — when they touch, a popup lets you choose how to bond them.
• Tap an atom by itself to give it a lone pair, remove it, or see nearby bonding options again.
• Ionically bonded atoms (like Na⁺ and Cl⁻) stay attached — drag one and its partner follows.
• Tap Check any time — a popup shows each atom's outer-shell electron count.