Periodic Table of Elements
Searchable periodic table of all 118 elements with atomic number, symbol, name, standard atomic weight and element category.
How to use
- 1Search by name, symbol or number.
- 2Use the molar mass calculator to add up atomic weights for a formula.
Frequently asked questions
What do the brackets around some masses mean?
Those elements have no stable isotopes; the number is the mass number of the longest-lived isotope.
Why is atomic weight not a whole number?
It's a weighted average of the element's natural isotopes — chlorine is about 75% ³⁵Cl and 25% ³⁷Cl, giving 35.45.
How many elements are there?
118 have been confirmed, up to oganesson (Og). Elements beyond uranium (92) are mostly made in laboratories.