# Roles of chemical elements

This table is designed to show the role(s) performed by each chemical element, in nature and in technology.
Z = Atomic number Sym. = Symbol Per. = Period Gr. = Group
| Z | Sym. | Element | Per. | Gr. | Role(s) in nature (non-living and living) | Role(s) in technology (old and new) |
| 1 | H | Hydrogen | 1 | 1 | Astronomy: source of power by nuclear fusion (proton–proton chain reaction and CNO cycle) Biology: One of the most common elements in living organisms | Petrochemical industry: hydrodealkylation, hydrodesulfurization Various industries: hydrogenation |
| 2 | He | Helium | 1 | 18 | Astronomy: source of power by nuclear fusion (alpha process and triple-alpha process) | Various industries: cryogenics, pressurization, controlled atmosphere, welding |
| 3 | Li | Lithium | 2 | 1 | | Ceramics and glass: flux, component of ovenware Electricity and electronics: batteries Various industries: lubricating greases |
| 4 | Be | Beryllium | 2 | 2 | | Radiography: radiation windows Aeronautics and astronautics: lightweight structural components |
| 5 | B | Boron | 2 | 13 | | Ceramics and glass: borosilicate glass Cleaning products: detergents and bleaches Insecticides: boric acid Electronics: semiconductors |
| 6 | C | Carbon | 2 | 14 | Biology: One of the most common elements in living organisms See also: Carbon-based life | Fossil fuels: coal, methane and petroleum Textile industry: cellulose Metallurgy: alloys, especially carbon steel |
| 7 | N | Nitrogen | 2 | 15 | Bacteria and archaea: nitrogen fixation by diazotrophs All forms of life on Earth: essential component of amino acids and of nucleic acids Earth's atmosphere, soil, and life forms: nitrogen cycle See also: CHON. | Chemical industry: nitrogen fixation by the Haber process Astronautics: nitric acid and hydrazine |
| 8 | O | Oxygen | 2 | 16 | Animals: inhaled in respiration Plants: exhaled in respiration; Biology: one of the most common elements in living organisms | Metallurgy: smelting of iron ore into steel Chemical industry: ethylene + O$_2$ —> ethylene oxide —> ethylene glycol —> many products Medicine Water treatment |
| 9 | F | Fluorine | 2 | 17 | | Various industries: fluorocarbons and derivatives as refrigerants and as anaesthetics Aluminium production: cryolite as solvent |
| 10 | Ne | Neon | 2 | 18 | | Signage: neon signs Electronics: vacuum tubes |
| 11 | Na | Sodium | 3 | 1 | See also: Sodium in biology. | |
| 12 | Mg | Magnesium | 3 | 2 | All life forms: essential catalyst for using and making DNA and RNA Plants: photosynthesis See also: Magnesium in biology. | Metallurgy: aluminium alloys, production of iron, steel, and titanium Automotive industry: lightweight components Electronics |
| 13 | Al | Aluminium | 3 | 13 | | |
| 14 | Si | Silicon | 3 | 14 | Earth's crust: silicate minerals Diatoms, radiolaria, and siliceous sponges: biogenic silica as a structural material | Construction: Portland cement, concrete Electronics: semiconductors |
| 15 | P | Phosphorus | 3 | 15 | Biology: structure of DNA and RNA part of adenosine triphosphate (ATP) structure of bones and teeth | Agriculture: fertilizers |
| 16 | S | Sulfur | 3 | 16 | Biology: part of the amino acids cysteine and methionine, and of all polypeptides, proteins, and enzymes that contain them See also: Sulfur assimilation. | Agriculture: fertilizers, fungicides, and pesticides |
| 17 | Cl | Chlorine | 3 | 17 | | |
| 18 | Ar | Argon | 3 | 18 | | |
| 19 | K | Potassium | 4 | 1 | Animals: neuron function, electrolyte balance See also: Potassium in biology. | Agriculture: fertilizers |
| 20 | Ca | Calcium | 4 | 2 | Animals: structure of bones and teeth See also: Calcium in biology. | Construction: cements and mortars |
| 21 | Sc | Scandium | 4 | 3 | | |
| 22 | Ti | Titanium | 4 | 4 | | |
| 23 | V | Vanadium | 4 | 5 | | |
| 24 | Cr | Chromium | 4 | 6 | | |
| 25 | Mn | Manganese | 4 | 7 | | |
| 26 | Fe | Iron | 4 | 8 | | |
| 27 | Co | Cobalt | 4 | 9 | | |
| 28 | Ni | Nickel | 4 | 10 | | |
| 29 | Cu | Copper | 4 | 11 | See also: Copper in health. | |
| 30 | Zn | Zinc | 4 | 12 | | |
| 31 | Ga | Gallium | 4 | 13 | | |
| 32 | Ge | Germanium | 4 | 14 | | |
| 33 | As | Arsenic | 4 | 15 | See also: Arsenic biochemistry. | |
| 34 | Se | Selenium | 4 | 16 | | |
| 35 | Br | Bromine | 4 | 17 | | |
| 36 | Kr | Krypton | 4 | 18 | | |
| 37 | Rb | Rubidium | 5 | 1 | | |
| 38 | Sr | Strontium | 5 | 2 | | |
| 39 | Y | Yttrium | 5 | 3 | | |
| 40 | Zr | Zirconium | 5 | 4 | | |
| 41 | Nb | Niobium | 5 | 5 | | |
| 42 | Mo | Molybdenum | 5 | 6 | | |
| 43 | Tc | Technetium | 5 | 7 | | |
| 44 | Ru | Ruthenium | 5 | 8 | | |
| 45 | Rh | Rhodium | 5 | 9 | | |
| 46 | Pd | Palladium | 5 | 10 | | |
| 47 | Ag | Silver | 5 | 11 | | |
| 48 | Cd | Cadmium | 5 | 12 | | |
| 49 | In | Indium | 5 | 13 | | |
| 50 | Sn | Tin | 5 | 14 | | |
| 51 | Sb | Antimony | 5 | 15 | | |
| 52 | Te | Tellurium | 5 | 16 | | |
| 53 | I | Iodine | 5 | 17 | See also: Iodine in biology. | |
| 54 | Xe | Xenon | 5 | 18 | | |
| 55 | Cs | Caesium | 6 | 1 | | |
| 56 | Ba | Barium | 6 | 2 | | |
| 57 | La | Lanthanum | 6 | 3 | | |
| 58 | Ce | Cerium | 6 | 3 | | |
| 59 | Pr | Praseodymium | 6 | 3 | | |
| 60 | Nd | Neodymium | 6 | 3 | | |
| 61 | Pm | Promethium | 6 | 3 | | |
| 62 | Sm | Samarium | 6 | 3 | | |
| 63 | Eu | Europium | 6 | 3 | | |
| 64 | Gd | Gadolinium | 6 | 3 | | |
| 65 | Tb | Terbium | 6 | 3 | | |
| 66 | Dy | Dysprosium | 6 | 3 | | |
| 67 | Ho | Holmium | 6 | 3 | | |
| 68 | Er | Erbium | 6 | 3 | | |
| 69 | Tm | Thulium | 6 | 3 | | |
| 70 | Yb | Ytterbium | 6 | 3 | | |
| 71 | Lu | Lutetium | 6 | 3 | | |
| 72 | Hf | Hafnium | 6 | 4 | | |
| 73 | Ta | Tantalum | 6 | 5 | | |
| 74 | W | Tungsten | 6 | 6 | | |
| 75 | Re | Rhenium | 6 | 7 | | |
| 76 | Os | Osmium | 6 | 8 | | |
| 77 | Ir | Iridium | 6 | 9 | | |
| 78 | Pt | Platinum | 6 | 10 | | |
| 79 | Au | Gold | 6 | 11 | | |
| 80 | Hg | Mercury | 6 | 12 | | |
| 81 | Tl | Thallium | 6 | 13 | | |
| 82 | Pb | Lead | 6 | 14 | | |
| 83 | Bi | Bismuth | 6 | 15 | | |
| 84 | Po | Polonium | 6 | 16 | | |
| 85 | At | Astatine | 6 | 17 | | |
| 86 | Rn | Radon | 6 | 18 | | |
| 87 | Fr | Francium | 7 | 1 | | |
| 88 | Ra | Radium | 7 | 2 | | |
| 89 | Ac | Actinium | 7 | 3 | | |
| 90 | Th | Thorium | 7 | 3 | | |
| 91 | Pa | Protactinium | 7 | 3 | | |
| 92 | U | Uranium | 7 | 3 | | |
| 93 | Np | Neptunium | 7 | 3 | | |
| 94 | Pu | Plutonium | 7 | 3 | | |
| 95 | Am | Americium | 7 | 3 | | |
| 96 | Cm | Curium | 7 | 3 | | |
| 97 | Bk | Berkelium | 7 | 3 | | |
| 98 | Cf | Californium | 7 | 3 | | |
| 99 | Es | Einsteinium | 7 | 3 | | |
| 100 | Fm | Fermium | 7 | 3 | | |
| 101 | Md | Mendelevium | 7 | 3 | | |
| 102 | No | Nobelium | 7 | 3 | | |
| 103 | Lr | Lawrencium | 7 | 3 | | |
| 104 | Rf | Rutherfordium | 7 | 4 | | |
| 105 | Db | Dubnium | 7 | 5 | | |
| 106 | Sg | Seaborgium | 7 | 6 | | |
| 107 | Bh | Bohrium | 7 | 7 | | |
| 108 | Hs | Hassium | 7 | 8 | | |
| 109 | Mt | Meitnerium | 7 | 9 | | |
| 110 | Ds | Darmstadtium | 7 | 10 | | |
| 111 | Rg | Roentgenium | 7 | 11 | | |
| 112 | Cn | Copernicium | 7 | 12 | | |
| 113 | Nh | Nihonium | 7 | 13 | | |
| 114 | Fl | Flerovium | 7 | 14 | | |
| 115 | Mc | Moscovium | 7 | 15 | | |
| 116 | Lv | Livermorium | 7 | 16 | | |
| 117 | Ts | Tennessine | 7 | 17 | | |
| 118 | Og | Oganesson | 7 | 18 | | |