Skip to content

Reference

The periodic table

All 118 elements. Atomic weights from IUPAC (2024), electron configurations and ionisation energies from NIST. Choose an element to see its details.

Find an element

Colour by

1HHydrogen1.0080 2HeHelium4.0026 3LiLithium6.94 4BeBeryllium9.0122 5BBoron10.81 6CCarbon12.011 7NNitrogen14.007 8OOxygen15.999 9FFluorine18.998 10NeNeon20.180 11NaSodium22.990 12MgMagnesium24.305 13AlAluminium26.982 14SiSilicon28.085 15PPhosphorus30.974 16SSulfur32.06 17ClChlorine35.45 18ArArgon39.95 19KPotassium39.098 20CaCalcium40.078 21ScScandium44.956 22TiTitanium47.867 23VVanadium50.942 24CrChromium51.996 25MnManganese54.938 26FeIron55.845 27CoCobalt58.933 28NiNickel58.693 29CuCopper63.546 30ZnZinc65.38 31GaGallium69.723 32GeGermanium72.630 33AsArsenic74.922 34SeSelenium78.971 35BrBromine79.904 36KrKrypton83.798 37RbRubidium85.468 38SrStrontium87.62 39YYttrium88.906 40ZrZirconium91.222 41NbNiobium92.906 42MoMolybdenum95.95 43TcTechnetium–44RuRuthenium101.07 45RhRhodium102.91 46PdPalladium106.42 47AgSilver107.87 48CdCadmium112.41 49InIndium114.82 50SnTin118.71 51SbAntimony121.76 52TeTellurium127.60 53IIodine126.90 54XeXenon131.29 55CsCaesium132.91 56BaBarium137.33 57LaLanthanum138.91 58CeCerium140.12 59PrPraseodymium140.91 60NdNeodymium144.24 61PmPromethium–62SmSamarium150.36 63EuEuropium151.96 64GdGadolinium157.25 65TbTerbium158.93 66DyDysprosium162.50 67HoHolmium164.93 68ErErbium167.26 69TmThulium168.93 70YbYtterbium173.05 71LuLutetium174.97 72HfHafnium178.49 73TaTantalum180.95 74WTungsten183.84 75ReRhenium186.21 76OsOsmium190.23 77IrIridium192.22 78PtPlatinum195.08 79AuGold196.97 80HgMercury200.59 81TlThallium204.38 82PbLead207.2 83BiBismuth208.98 84PoPolonium–85AtAstatine–86RnRadon–87FrFrancium–88RaRadium–89AcActinium–90ThThorium232.04 91PaProtactinium231.04 92UUranium238.03 93NpNeptunium–94PuPlutonium–95AmAmericium–96CmCurium–97BkBerkelium–98CfCalifornium–99EsEinsteinium–100FmFermium–101MdMendelevium–102NoNobelium–103LrLawrencium–104RfRutherfordium–105DbDubnium–106SgSeaborgium–107BhBohrium–108HsHassium–109MtMeitnerium–110DsDarmstadtium–111RgRoentgenium–112CnCopernicium–113NhNihonium–114FlFlerovium–115McMoscovium–116LvLivermorium–117TsTennessine–118OgOganesson–

The two rows at the bottom belong in periods 6 and 7; they are printed separately so the table fits. A dash for the atomic weight means the element has no stable isotopes, so it has no standard atomic weight. Elements from 104 on have only been made a few atoms at a time; their families are predictions.

How to read it

Each box gives the atomic number (the number of protons), the symbol, the name and the standard atomic weight, which is the relative atomic mass of the element as found on Earth. The rows are periods: every element in a period has the same number of electron shells. The columns are groups, numbered 1 to 18: elements in a group have the same arrangement of outer electrons, so they react in similar ways.

Families such as the halogens and noble gases are conventions, and their edges are argued about. Hydrogen sits above group 1 but is not an alkali metal. Where lanthanum, lutetium, actinium and lawrencium belong is still discussed by IUPAC; this table follows the layout of the IUPAC periodic table, with all fifteen of each series in the bottom rows. IUPAC recommends the names lanthanoids and actinoids, though lanthanides and actinides are still common.

Every colouring has a code or value printed in the corner of each box too, so you don’t need to tell colours apart to use it.

All 118 elements