Animated Periodic Table
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Valence electrons

The outer electrons that do the bonding. The number on each tile is how many an element has.

Main-group elements: the group number tells you the valence electrons (groups 13–18: subtract 10). * Transition and inner-transition metals show their outer-shell count; inner d or f electrons can also bond.

1HHydrogen12HeHelium23LiLithium14BeBeryllium25BBoron36CCarbon47NNitrogen58OOxygen69FFluorine710NeNeon811NaSodium112MgMagnesium213AlAluminum314SiSilicon415PPhosphorus516SSulfur617ClChlorine718ArArgon819KPotassium120CaCalcium221ScScandium2*22TiTitanium2*23VVanadium2*24CrChromium1*25MnManganese2*26FeIron2*27CoCobalt2*28NiNickel2*29CuCopper1*30ZnZinc2*31GaGallium332GeGermanium433AsArsenic534SeSelenium635BrBromine736KrKrypton837RbRubidium138SrStrontium239YYttrium2*40ZrZirconium2*41NbNiobium1*42MoMolybdenum1*43TcTechnetium2*44RuRuthenium1*45RhRhodium1*46PdPalladium18*47AgSilver1*48CdCadmium2*49InIndium350SnTin451SbAntimony552TeTellurium653IIodine754XeXenon855CsCesium156BaBarium257LaLanthanum2*58CeCerium2*59PrPraseodymium2*60NdNeodymium2*61PmPromethium2*62SmSamarium2*63EuEuropium2*64GdGadolinium2*65TbTerbium2*66DyDysprosium2*67HoHolmium2*68ErErbium2*69TmThulium2*70YbYtterbium2*71LuLutetium2*72HfHafnium2*73TaTantalum2*74WTungsten2*75ReRhenium2*76OsOsmium2*77IrIridium2*78PtPlatinum1*79AuGold1*80HgMercury2*81TlThallium382PbLead483BiBismuth584PoPolonium685AtAstatine786RnRadon887FrFrancium188RaRadium289AcActinium2*90ThThorium2*91PaProtactinium2*92UUranium2*93NpNeptunium2*94PuPlutonium2*95AmAmericium2*96CmCurium2*97BkBerkelium2*98CfCalifornium2*99EsEinsteinium2*100FmFermium2*101MdMendelevium2*102NoNobelium2*103LrLawrencium2*104RfRutherfordium2*105DbDubnium2*106SgSeaborgium2*107BhBohrium2*108HsHassium2*109MtMeitnerium2*110DsDarmstadtium2*111RgRoentgenium2*112CnCopernicium2*113NhNihonium3114FlFlerovium4115McMoscovium5116LvLivermorium6117TsTennessine7118OgOganesson8
Bohr model of Oxygen: 8 protons and 8 neutrons in the nucleus; electrons by shell 2, 6
O8 · Oxygen
Nonmetal
Atomic mass
15.999
Per shell
2, 6
Valence electrons
6
Protons · neutrons
8 · 8
Configuration
[He] 2s² 2p⁴

Oxygen: full facts and animations

Watch the outer shell fill across period 2

Each step right adds one valence electron (orange). Lithium has 1 and is desperate to lose it; fluorine has 7 and grabs one more; neon's 8 make a full shell, so it barely reacts.

Bohr model of Lithium: 3 protons and 4 neutrons in the nucleus; electrons by shell 2, 1Li: 1
Bohr model of Beryllium: 4 protons and 5 neutrons in the nucleus; electrons by shell 2, 2Be: 2
Bohr model of Boron: 5 protons and 6 neutrons in the nucleus; electrons by shell 2, 3B: 3
Bohr model of Carbon: 6 protons and 6 neutrons in the nucleus; electrons by shell 2, 4C: 4
Bohr model of Nitrogen: 7 protons and 7 neutrons in the nucleus; electrons by shell 2, 5N: 5
Bohr model of Oxygen: 8 protons and 8 neutrons in the nucleus; electrons by shell 2, 6O: 6
Bohr model of Fluorine: 9 protons and 10 neutrons in the nucleus; electrons by shell 2, 7F: 7
Bohr model of Neon: 10 protons and 10 neutrons in the nucleus; electrons by shell 2, 8Ne: 8

How to find valence electrons

  1. Find the element's group (column) number.
  2. Groups 1 and 2: the valence electrons equal the group number.
  3. Groups 13 to 18: subtract 10. Oxygen is in group 16, so it has 6.
  4. Transition metals (groups 3–12): usually 2 outer electrons, but inner d electrons can also bond.

Valence electron questions

What are valence electrons?

The electrons in an atom's outermost shell. They are the ones that form bonds, so they decide how an element reacts.

How do you find valence electrons on the periodic table?

For main-group elements use the group number: groups 1 and 2 have 1 and 2; for groups 13 to 18, subtract 10 (group 16 has 6). Helium is the exception with 2.

How many valence electrons do transition metals have?

It varies. Most have 2 in their outer s subshell, but electrons in the d subshell just below can also take part in bonding, which is why many transition metals form several different ions.