Explore all 118 elements with detailed properties: atomic mass, electron configuration, electronegativity, ionization energy, atomic radius, and more.
The periodic table is chemistry's single most information-dense reference tool, and knowing how to actually read element-specific data from it — not just recite trend directions — is what separates surface-level familiarity from exam-ready fluency for AP Chemistry, USNCO, and IChO.
Every element's position encodes real physical data: atomic mass (the weighted average of naturally occurring isotopes), electron configuration (which follows directly from an element's group and period position via the Aufbau principle), and a full set of measured properties including electronegativity, ionization energy, and atomic radius. Being able to look up any element and immediately see its full data profile — rather than deriving it from scratch each time — is essential for working through multi-step problems quickly under exam time pressure.
Color-coded overlays make trends visually obvious across the entire table simultaneously, rather than one group or period at a time. An electronegativity overlay immediately shows fluorine as the most electronegative element (3.98 on the Pauling scale) sitting in the top-right corner, while francium and cesium — the least electronegative — sit in the bottom-left, illustrating the diagonal trend that increases up and to the right. The same visual logic applies to ionization energy and atomic radius overlays, each revealing the underlying pattern of increasing effective nuclear charge across a period and increasing shielding down a group.
Electron configuration display for every element, including the notable exceptions like chromium ([Ar]3d⁵4s¹ instead of the "expected" [Ar]3d⁴4s²) and copper ([Ar]3d¹⁰4s¹), reinforces that half-filled and fully-filled d subshells carry extra stability — a detail frequently tested precisely because it breaks the naive pattern-matching approach.
This interactive periodic table lets you click any of all 118 elements to view its complete property profile, switch between color-coded trend overlays, and compare multiple elements side by side — a full element-by-element reference built for fast lookup during problem sets and exam review.