Periodic Table of the Elements

Periodic Table shows all 118 known elements in the standard 18-column layout, coloured by block. Select an element — by clicking it, moving with the arrow keys, or typing its name, symbol or atomic number in the search box — to see its atomic number, standard atomic weight, period, group, block, and the IUPAC collective name it belongs to, such as alkali metal, halogen, noble gas or lanthanoid. Atomic weights are IUPAC’s abridged standard atomic weights (2021), the same values the molar mass and mole calculators use. For an element with no stable isotope, the mass number of its longest-lived isotope is shown in brackets, as on printed tables. A List view shows every element in a table that can be read row by row, which also suits screen readers and small screens.

1. Type a name, symbol or atomic number to find an element; others dim and the first match is selected.
2. Or click any element, or use the arrow keys to move across the table (Home and End jump to the ends of a row).
3. Read its details in the panel above the table.
4. Choose List to see all the elements as a table.

• Colours show the block (s, p, d, f), which follows from an element’s position. The traditional metal and non-metal classes are not drawn, because their borders — polonium, astatine, the newest elements — are disputed.
• Collective names follow IUPAC’s 2005 recommendations, which list members for each name. Elements discovered or named since, such as tennessine, are not given one.
• Where lanthanum and actinium or lutetium and lawrencium belong in group 3 is still debated; this table follows IUPAC’s own layout, with all fifteen of each in the rows below.
• Electron configurations, densities and melting points are not shown: the page keeps to values taken from IUPAC’s tables.
• The table is part of the page and works offline. Nothing you search for is sent or saved.

The element has no stable isotope and no standard atomic weight. The bracketed number is the mass number of its longest-lived known isotope, for example [222] for radon.

Natural chlorine is a mixture of chlorine-35 and chlorine-37. The atomic weight is the average over that mix, weighted by how common each isotope is.

They group elements by the kind of orbital their outermost electrons fill. The s-block is groups 1 and 2 plus helium, the p-block groups 13–18, the d-block groups 3–12 and the f-block the lanthanoids and actinoids.

118 have been discovered and named, up to oganesson. Elements beyond uranium (92) are made artificially, and those past about 100 exist only a few atoms at a time.