Colophon
A periodic table built like an instrument, not a poster.
Most periodic tables online are a picture with links on it. This one is a dataset you can interrogate, a set of renderers that draw what physics actually says, and a handful of calculators that do the arithmetic properly.
Real orbitals, not Bohr rings
The 3D views on every element page are Monte-Carlo samples of |ψ|² — the actual hydrogenic wavefunction, with the associated-Laguerre radial part and real spherical harmonics evaluated in the browser. Lobe colour encodes the sign of the wavefunction, which is the thing that makes bonding work. Nothing here is a stock illustration.
Arithmetic, not lookup tables
The equation balancer builds the element-conservation matrix and solves it over exact rationals, so redox equations come out in the same single step as burning hydrogen. The molar-mass parser handles nesting, hydrates and charges. Everything runs locally.
Gaps are shown as gaps
Where a value has never been measured, this site prints a dash rather than an invented number. Predicted values for the superheavy elements are marked. Three noble gases genuinely have no Pauling electronegativity, and the table says so.
Where the numbers come from
Standard atomic weights follow the IUPAC 2021 table. Physical constants — melting and boiling points, densities, radii, ionisation energies, electron affinities, specific heats and thermal conductivities — follow the CRC Handbook of Chemistry and Physics and NIST reference data.
Two conventions worth knowing. Temperatures are stored in kelvin and converted for display, because kelvin is the only scale on which ratios mean anything. Densities are given in g/cm³ for solids and liquids at 293 K, and for gases at 273 K and one atmosphere, which is why hydrogen reads 0.00009 rather than something friendlier.
What the colours mean
Element family colours run as a single hue sweep in roughly periodic-table reading order — red at the alkali metals, through gold at the transition metals and cyan at the nonmetals, to violet and magenta at the f-block. The sequence is deliberate: adjacent families get adjacent hues, so the map reads as a gradient rather than a set of arbitrary labels, and the palette holds up under the common forms of colour blindness.
Everywhere else the interface stays close to monochrome. Saturated colour is reserved for things that carry meaning: family, state of matter, hazard, and measured value.
What is deliberately missing
There is no quiz, no login, no leaderboard and no newsletter. Nothing you type is transmitted. The element index is one cached request; every calculation after that happens on your machine.
Go and break something.
Build a nuclide that cannot exist. Scrub the table to 5,778 K and watch iron boil. Balance an equation you were dreading.