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Reference resource

Periodic table of the elements

All 118 chemical elements with their essential data: atomic weight, density, melting and boiling points, state at 20 °C, appearance, category and electron configuration. Click any element to open its full fact sheet.

118 elementsSources: CIAAW 2024 · IUPAC 2022 · CRC HandbookCC BY 4.0

alkali metalalkaline earth metaltransition metalpost-transition metalmetalloidnonmetalhalogennoble gaslanthanideactinide

How to read this table

  • Atomic weight: CIAAW 2024 standard values. Conventional values are published for elements with a natural interval. Numbers in brackets are not atomic weights: they give the mass number of the nuclide with the longest confirmed half-life (IUPAC 2022 criterion).
  • A «—» value means no reliable experimental measurement exists; the element's fact sheet explains why. No number in this table is invented.
  • Densities of solids and liquids at 20 °C; gases at 0 °C and 1 atm (in g/L).
  • Estimates: francium and astatine have never been observed in macroscopic quantity; their melting and boiling points are estimates, marked as such.
  • Superheavy elements (Rf–Og): no experimental melting, boiling or density data; their electron configurations are theoretical predictions.

Sources

  • Atomic weights: CIAAW — Standard Atomic Weights 2024 (ciaaw.org), based on "Atomic Weights 2021" (Meija et al., Pure Appl. Chem. 2022) + 2024 revisions.
  • Bracketed masses: official Periodic Table of the Elements image, IUPAC, May 4, 2022.
  • Densities, melting and boiling points: "List of chemical elements" (Wikipedia, accessed 2026-09-28) cross-checked against mendeleev 1.3.0; disagreements resolved with the CRC Handbook of Chemistry and Physics (and WebElements for francium).
  • Electron configurations: mendeleev 1.3.0.
  • Compiled September 28, 2026 by Muse (Milo) for JCEA / mathvsmyth.com — CC BY 4.0. Machine-readable dataset: tabla-periodica.json.