Interactive

The periodic table

All 118 elements, arranged in order of atomic number so that structure predicts behaviour: elements in the same column (group) have the same outer-shell electron count and react alike, and each row (period) fills one more shell. Select a cell for its electron configuration, common oxidation states, phase, a shell diagram, and a note on where it turns up. Colour the table by a property, compare elements side by side, search by name, symbol, or number, or move with the arrow keys.

Colour by

Atomic radiusGrows down a group as shells are added; shrinks left→right across a period as the growing nuclear charge pulls the same shell in tighter.

Ionisation energyThe energy to remove the outermost electron. Falls down a group (the electron is farther out and screened); rises left→right. Helium is the maximum (2372 kJ/mol); caesium and francium are among the lowest (~376-380 kJ/mol).

ElectronegativityPull on shared electrons in a bond. Falls down a group; rises left→right. Fluorine is the maximum (3.98); caesium and francium the minimum.

Metallic characterThe opposite pattern: strongest at the bottom left (caesium, francium), weakest at the top right. The metalloid staircase (B–Si–As–Te) marks the transition.