Interactive periodic table
Click any element for its atomic mass, group, period, electronegativity, and particle counts. Every box shows its electronegativity, and each column is labeled with its group and usual ion charge. Use the type buttons to highlight a family, or search by name, symbol, or number.
The small number at the bottom of each box is Pauling electronegativity. Labels above each column show the group (1A–8A, 3B–2B) and the usual ion charge for main-group elements. "Nonmetal" highlights halogens too, since they are nonmetals; "Halogen" shows only group 7A. Scroll sideways on a phone to see the whole table. For full electron configurations and orbital diagrams, use the electron configuration calculator.
Using the table
Elements are arranged by atomic number, which is the number of protons. Rows are periods, and columns are groups of elements with similar chemistry. The two rows below the table are the lanthanides and actinides, which belong between groups 2 and 3.
Atomic masses are rounded standard values, the same ones used by the molar mass calculator. For elements with no stable isotopes, the number shown is the mass number of the most stable isotope instead. Neutron counts are an estimate for the most common isotope.
How to read an element tile
Each tile shows the atomic number (the number of protons, which defines the element) and the symbol. Click it to see the standard atomic weight in g/mol, an average over the element’s natural isotopes, along with its group, period and particle counts. For a neutral atom, electrons = atomic number, and neutrons ≈ mass number − atomic number for a given isotope. Carbon-12, for example, has 6 protons, 6 neutrons and 6 electrons.
Columns are groups: elements in a group have the same number of valence electrons and similar chemistry, like the alkali metals in group 1. Rows are periods: the period number tells you the highest electron shell that is filling.
Frequently asked questions
How many elements are there?
There are 118 confirmed elements, from hydrogen (1) to oganesson (118). Elements past uranium (92) are mostly synthetic and very short-lived.
Why do some elements show a whole number instead of a decimal mass?
Elements with no stable isotopes, such as technetium and the heaviest elements, don’t have a standard atomic weight. The table shows the mass number of their longest-lived isotope instead.
Which elements are metalloids?
The common list is boron, silicon, germanium, arsenic, antimony and tellurium, along the staircase between metals and nonmetals. Some textbooks also include polonium or astatine.
How do I find valence electrons from the table?
For main-group elements, use the group number: groups 1 and 2 have 1 and 2 valence electrons, and groups 13 to 18 have the group number minus 10 (so oxygen in group 16 has 6). Helium is the exception with 2. The Lewis structure generator uses these counts.