Where the data comes from
One open dataset. Nothing invented.
Every number on this site — masses, melting points, electron shells, all of it — comes from one openly licensed dataset, fetched by an open script, shown exactly as published.
The pipeline
1 · Fetch
An open script downloads the published dataset directly from its source. If the source is down, the script fails — it never invents or fills in a value.
2 · Check & trim
The script verifies all 118 confirmed elements are present with the fields this site shows, keeps only those fields, and drops hypothetical elements beyond 118 — the only two things it ever does to the data. Hypothetical elements beyond 118 are not shown: 119 Ununennium (predicted, never observed).
3 · Snapshot
The result is stored with its provenance — source URL, license, retrieval date (2026-08-21) — beside every number, and this page links straight back to the original.
The source
Periodic-Table-JSON (Bowserinator and contributors); element summaries derived from Wikipedia, published under CC BY-SA 3.0. Element summaries are drawn from Wikipedia articles (each element page links to its original). 118 elements in this snapshot.
Units, as published: Units as published by the dataset: temperatures in kelvin (K); density in g/cm³ for solids and liquids, g/L for gases; atomic mass in unified atomic mass units (u); ionization energies and electron affinity in kJ/mol.
The compounds source
The 52 compounds come from PubChem, National Center for Biotechnology Information, U.S. National Library of Medicine — Public domain (PubChem, U.S. National Institutes of Health), which permits any reuse. A second pipeline script fetches them by their PubChem identifiers; molecular weights and dissociation constants (pKa) are stored verbatim as published, and the only computation is parsing each formula into element counts (checked against the 118 elements).
Curation, disclosed: This is a curated selection of everyday compounds, not a database: which compounds appear, their everyday names, tags, and "commonly met as" acid/base roles are editorial choices. Every number and name beside them comes from PubChem verbatim. Snapshot retrieved 2026-08-21.
Is it okay that this comes from Wikipedia?
Yes — that's what the license is for. Wikipedia's text and this dataset are published under Creative Commons BY-SA, which explicitly allows anyone to reuse them, including in products, on two conditions: credit the source (done — this page, and every element page, links straight back) and share the text under the same license — so the element summaries you read here remain CC BY-SA, as they should.
Worth being honest about what that means: the summaries are encyclopedic writing — community-written and community-reviewed — while the numbers (masses, melting points, shells) are physical constants the dataset compiled from reference sources. For a future version, primary scientific databases (NIST, IUPAC, PubChem) are the upgrade path for the numbers; the pipeline was built so a new source slots in without changing the app.
What we won't do
- No invented values. Where the dataset has no number (some densities, melting points, and the chemistry of the newest elements), the page shows a dash and says so.
- Predicted ≠ confirmed. Elements whose chemistry has never been observed are labeled that way — and hypothetical elements beyond 118 aren't shown at all.
- Depth, not dumbing down. The Simple / Everyday / Student / Deep dive tabs on every element page tell the same facts at different depths — none of them a different truth.