Editing Radionuclide (section)

==Examples==
The following table lists properties of selected radionuclides illustrating the range of properties and uses.
{|  class="wikitable sortable"
! Isotope !! ''Z'' !! ''N'' !! half-life !! DM !! DE<br /> [[keV]] !! Mode of formation !! Comments

|-
! [[Tritium]] (<sup>3</sup>H)
| 1 || 2 || 12.3 y || [[beta decay|β]]{{sup|−}} || 19 || Cosmogenic || lightest radionuclide, used in artificial [[nuclear fusion]], also used for [[radioluminescence]] and as oceanic transient tracer. Synthesized from neutron bombardment of [[lithium-6]] or [[deuterium]]
|-
! [[Beryllium-10]]
| 4 || 6 || 1,387,000 y || β{{sup|−}} || 556
| Cosmogenic || used to examine soil erosion, soil formation from regolith, and the age of ice cores
|-
! [[Carbon-14]]
| 6 || 8 || 5,700 y || β{{sup|−}} || 156
| Cosmogenic || used for [[radiocarbon dating]]
|-
! [[Fluorine-18]]
| 9 || 9 || 110 min || β{{sup|+}}, [[Electron Capture|EC]] || 633/1655
| Cosmogenic || positron source, synthesised for use as a medical [[radiotracer]] in [[positron emission tomography|PET scans]].
|-
! [[Aluminium-26]]
| 13 || 13|| 717,000 y || β{{sup|+}}, [[Electron Capture|EC]] || 4004
| Cosmogenic || exposure dating of rocks, sediment
|-
! [[Chlorine-36]]
| 17 || 19 || 301,000 y || β{{sup|−}}, [[Electron Capture|EC]] ||  709
| Cosmogenic || exposure dating of rocks, groundwater tracer
|-
! [[Potassium-40]]
| 19 || 21 || 1.24{{E|9}} y || β{{sup|−}}, [[Electron Capture|EC]] || 1330 /1505
| Primordial || used for [[potassium-argon dating]], source of atmospheric [[argon]], source of [[radiogenic heat]], largest source of natural radioactivity
|-
! [[Isotopes of calcium|Calcium-41]]
| 20 || 21 || 99,400 y || EC ||
| Cosmogenic || exposure dating of [[carbonate rocks]]
|-
! [[Cobalt-60]]
| 27 || 33 || 5.3 y || β{{sup|−}} || 2824
| Synthetic ||  produces high energy gamma rays, used for radiotherapy, equipment sterilisation, food irradiation
|-
! [[Krypton-81]]
| 36 || 45 || 229,000 y || β{{sup|+}} || || Cosmogenic || groundwater dating
|-
! [[Strontium-90]]
| 38 || 52 || 28.8 y || β{{sup|−}} || 546
| Fission product || [[medium-lived fission product]]; probably most dangerous component of nuclear fallout
|-
! [[Technetium-99]]
| 43 || 56 || 210,000 y || β{{sup|−}} || 294
| Fission product || most common isotope of the lightest unstable element, most significant of [[long-lived fission products]]
|-
! [[Technetium-99m]]
| 43 || 56 || 6 hr || [[gamma ray|γ]],IC || 141
| Synthetic || most commonly used medical radioisotope, used as a radioactive tracer
|-
! [[Iodine-129]]
| 53 || 76 || 15,700,000 y || β{{sup|−}} || 194
| Cosmogenic || longest lived [[fission product]]; groundwater tracer
|-
! [[Iodine-131]]
| 53 || 78 || 8 d || β{{sup|−}} || 971
| Fission product || most significant short-term health hazard from nuclear fission, used in nuclear medicine, industrial tracer
|-
! [[Xenon-135]]
| 54 || 81 || 9.1 h || β{{sup|−}} || 1160
| Fission product|| strongest known "nuclear poison" (neutron-absorber), with a major effect on nuclear reactor operation.
|-
! [[Caesium-137]]
| 55 || 82 || 30.2 y || β{{sup|−}} || 1176
| Fission product || other major [[medium-lived fission product]] of concern
|-
! [[Gadolinium-153]]
| 64 || 89 || 240 d || EC ||
| Synthetic || Calibrating nuclear equipment, bone density screening
|-
! [[Bismuth-209]]
| 83 || 126 || 2.01{{E|19}}y || [[alpha decay|α]] || 3137
| Primordial || long considered stable, decay only detected in 2003
|-
! [[Polonium-210]]
| 84 || 126 || 138 d || α || 5307
| Decay product || Highly toxic, used in [[poisoning of Alexander Litvinenko]]
|-
! [[Radon-222]]
| 86 || 136 || 3.8 d || α || 5590
| Decay product || gas, responsible for the majority of public exposure to ionizing radiation, second most frequent cause of lung cancer
|-
! [[Thorium-232]]
| 90 || 142 || 1.4{{E|10}} y  || α || 4083
| Primordial || basis of [[thorium fuel cycle]]
|-
! [[Uranium-235]]
| 92 || 143 || 7{{E|8}}y || α || 4679
| Primordial || [[fissile]], main nuclear fuel
|-
! [[Uranium-238]]
| 92 || 146 || 4.5{{E|9}} y || α || 4267
| Primordial || Main Uranium isotope
|-
! [[Plutonium-238]]
| 94 || 144 || 87.7 y || α || 5593
| Synthetic || used in radioisotope thermoelectric generators (RTGs) and radioisotope heater units as an energy source for spacecraft
|-
! [[Plutonium-239]]
| 94 || 145 || 24,110 y || α || 5245
| Synthetic || used for most modern nuclear weapons
|-
! [[Americium-241]]
| 95 || 146 || 432 y || α || 5486
| Synthetic || used in household smoke detectors as an ionising agent
|-
! [[Californium-252]]
| 98 || 154 || 2.64 y || α/SF || 6217
| Synthetic || undergoes spontaneous fission (3% of decays), making it a powerful neutron source, used as a reactor initiator and for detection devices
|}
Key: ''Z''&nbsp;=&nbsp;[[atomic number]]; ''N''&nbsp;=&nbsp;[[neutron number]]; DM&nbsp;=&nbsp;decay mode; DE&nbsp;=&nbsp;decay energy; EC&nbsp;=&nbsp;[[electron capture]]

===Household smoke detectors===
[[File:Americium-241.jpg|thumb|Americium-241 container in a smoke detector.]]

[[File:Americium-241 Sample from Smoke Detector.JPG|thumb|Americium-241 capsule as found in smoke detector. The circle of darker metal in the center is americium-241; the surrounding casing is aluminium.]]

Radionuclides are present in many homes as they are used inside the most common household [[smoke detector]]s. The radionuclide used is [[americium-241]], which is created by bombarding plutonium with neutrons in a nuclear reactor. It decays by emitting [[alpha particle]]s and [[gamma radiation]] to become [[neptunium-237]]. Smoke detectors use a very small quantity of <sup>241</sup>Am (about 0.29 micrograms per smoke detector) in the form of [[americium dioxide]]. <sup>241</sup>Am is used as it emits alpha particles which ionize the air in the detector's [[ionization chamber]]. A small electric voltage is applied to the ionized air which gives rise to a small electric current. In the presence of smoke, some of the ions are neutralized, thereby decreasing the current, which activates the detector's alarm.<ref>{{cite web|url=http://www.world-nuclear.org/info/inf57.html|title=Smoke Detectors and Americium|work=world-nuclear.org|url-status=dead|archive-url=https://web.archive.org/web/20101112082137/http://www.world-nuclear.org/info/inf57.html|archive-date=2010-11-12}}</ref><ref>[http://www.doh.wa.gov/ehp/rp/factsheets/factsheets-htm/fs23am241.htm Office of Radiation Protection – Am 241 Fact Sheet – Washington State Department of Health] {{webarchive|url=https://web.archive.org/web/20110318173013/http://www.doh.wa.gov/ehp/rp/factsheets/factsheets-htm/fs23am241.htm |date=2011-03-18 }}</ref>