How to use it
- Click any element (or move with the arrow keys) to see its atomic weight, electron configuration, oxidation states, electronegativity, radius, ionization energy, melting and boiling points, density and discovery year.
- Use Color by to shade the table by category, block, or any numeric property, such as electronegativity or density, on a color scale with a legend.
- Choose State at a temperature and drag the slider, or type a temperature in °C, °F or kelvin, to see which elements are solid, liquid or gas at that temperature.
- Type a name, symbol or atomic number in Find to jump to it. Download SVG saves the colored table as an image; Download data saves all 118 elements as a spreadsheet file.
Where the data comes from, and why it matters
Many online periodic tables copy one large data set and show its numbers as they are. We started from PubChem’s periodic table, the National Institutes of Health chemistry database, and checked it against the primary sources before using it. Two properties did not hold up:
| Property | Primary source | What we found in the PubChem values | What this table shows |
|---|---|---|---|
| Standard atomic weight | IUPAC’s Commission on Isotopic Abundances and Atomic Weights (CIAAW), abridged values | 49 of the 84 elements with a standard weight are rounded differently, for example lithium 7.0 instead of 6.94, argon 39.9 instead of 39.95, iron 55.84 instead of 55.845 | the CIAAW value with its stated uncertainty |
| First ionization energy | NIST Atomic Spectra Database | 21 of 102 values differ by more than 0.01 eV; the largest is tantalum, 7.89 eV against NIST’s 7.5496 eV | the NIST value |
The remaining properties (electronegativity on the Pauling scale, van der Waals radius, electron affinity, melting and boiling points, density, oxidation states, electron configuration and discovery year) are PubChem’s, shown unchanged. Elements with no stable isotopes, such as technetium and everything above bismuth except thorium, protactinium and uranium, have no standard atomic weight; for those the table shows the mass number of a long-lived isotope in brackets, as most printed tables do.
States of matter at any temperature
The state view compares the chosen temperature with each element’s melting and boiling point at normal atmospheric pressure. At room temperature (25 °C) it shows 11 gases, 2 liquids (bromine and mercury) and the rest solid, matching PubChem’s listed standard state for all 103 elements where both are known. Gallium (melting at 29.8 °C) and cesium (28.4 °C) are solid at room temperature but melt in a warm hand, which you can see by moving the slider to body temperature.
Three listed values do not describe normal pressure, so the table handles them separately. Helium never freezes at atmospheric pressure, however cold it gets; its listed melting point needs about 25 atmospheres. Arsenic and carbon have no liquid phase at atmospheric pressure: arsenic turns straight from solid to gas (sublimes) at 887 K, and carbon sublimes at a very high temperature. The 15 heaviest elements, from rutherfordium up, have been made only a few atoms at a time and have no measured melting point, so they show as unknown.
How the table is laid out
The layout follows the International Union of Pure and Applied Chemistry: 18 numbered groups, with the 15 lanthanides (lanthanum to lutetium) and 15 actinides (actinium to lawrencium) in two rows underneath and a 57–71 and 89–103 marker in group 3. Coloring by block shows where each element’s outermost electrons go: s-block (groups 1 and 2, plus helium), p-block (groups 13 to 18), d-block (groups 3 to 12) and f-block (the two lower rows).
What we tested
On October 15, 2026 we checked the page’s own data and functions. All 84 standard atomic weights match CIAAW’s published table character for character, all 108 ionization energies match NIST, and every other field matches the PubChem download it came from. Every element sits in the right place: groups 1, 2, 3, 12, 13, 17 and 18 hold exactly the elements they should, the periods hold 2, 8, 8, 18, 18, 32 and 32 elements, and the blocks hold 14, 36, 38 and 30. The phase rules give helium as liquid at 2 K, mercury as liquid at 0 °C, arsenic as a gas at 1,000 K and tungsten as a gas at 6,000 K. Text on every one of the 373 cell colors the table can show has at least 4.52:1 contrast (WCAG AA asks for 4.5:1), and the downloaded data file opens as 118 rows of 21 columns. In Chromium: all 118 elements rendered with no overlapping cells; iron opened showing 55.845 ± 0.002 and NIST's 7.9025 eV; clicking, arrow keys (gold up to silver, right to cadmium) and search by symbol and number selected the right element; at room temperature the state view showed 2 liquids and 11 gases, and at body temperature (37 °C) 4 liquids, with gallium and cesium melted; helium stayed liquid at 1 K; the CSV opened as 118 rows of 21 columns and the SVG held 118 tiles; settings survived a reload; the page fitted a 390 px phone with no errors. We also checked the check: putting PubChem’s rounded weight for iron back into the data made the comparison with CIAAW fail.
Sources
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