Explore all 118 elements — click any element for details
This interactive periodic table displays all 118 confirmed chemical elements arranged by atomic number, from hydrogen (1) to oganesson (118), in the standard 18-column, 7-period layout with the lanthanide and actinide series set out below. Click any element cell to open a detail view showing its symbol, atomic number, standard atomic weight, electron configuration, group and period, element category (alkali metal, halogen, noble gas, transition metal, and so on), and common physical properties such as state at room temperature.
It is built for chemistry and physics students, teachers preparing lessons, and anyone who needs a quick, offline-friendly reference while solving stoichiometry, molar mass, or electron-configuration problems. Color coding by element category makes periodic trends easy to spot at a glance.
Elements are ordered by increasing atomic number (Z), which equals the number of protons in the nucleus. Reading left to right and top to bottom follows this sequence exactly, so each element has one more proton than the one before it. Elements in the same vertical group share the same number of valence electrons, which is why they behave chemically alike.
The table is divided into blocks based on the highest-energy electron subshell being filled: the s-block (groups 1 to 2), the p-block (groups 13 to 18), the d-block (transition metals, groups 3 to 12), and the f-block (lanthanides and actinides). Electron configuration follows this pattern, for example carbon (Z=6) is 1s2 2s2 2p2 and iron (Z=26) is [Ar] 3d6 4s2.
Periodic trends emerge from this structure. Atomic radius generally decreases across a period and increases down a group, while electronegativity and ionization energy increase across a period and decrease down a group. Standard atomic weights are the IUPAC abundance-weighted averages of an element's naturally occurring isotopes, which is why they are not whole numbers, for example chlorine at about 35.45.
Yes, it is completely free with no sign-up required. It runs entirely in your browser and does not send any input to a server, so there is nothing to track or store.
It includes all 118 elements officially named and recognized by IUPAC, ending with oganesson (element 118). This covers every element on the modern standard periodic table.
Atomic weight is the weighted average mass of all naturally occurring isotopes of an element, based on their relative abundance. That average rarely lands on a whole number, for example chlorine is about 35.45 because it is a mix of chlorine-35 and chlorine-37.
The atomic number is the count of protons in the nucleus and defines the element; it is always a whole number. Atomic weight is the average mass of the atom in atomic mass units and accounts for isotopes, so it is typically a decimal.
Yes. Add up the atomic weight of every atom in a chemical formula, for example water (H2O) is roughly 2(1.008) + 15.999, which equals about 18.02 grams per mole.
Colors group elements by category, such as alkali metals, alkaline earth metals, transition metals, halogens, noble gases, metalloids, and nonmetals. This makes it easy to see which elements share similar chemical behavior.
They are shown in two separate rows below the main body of the table. This is a standard convention that keeps the table compact, since these f-block series would otherwise stretch it far too wide.