There are 39 known isotope

Isotope

Isotopes are variants of atoms of a particular chemical element, which have differing numbers of neutrons. Atoms of a particular element by definition must contain the same number of protons but may have a distinct number of neutrons which differs from atom to atom, without changing the designation...

s of radon

Radon

Radon is a chemical element with symbol Rn and atomic number 86. It is a radioactive, colorless, odorless, tasteless noble gas, occurring naturally as the decay product of uranium or thorium. Its most stable isotope, 222Rn, has a half-life of 3.8 days...

(Rn) from ¹⁹³Rn to ²³¹Rn. The most stable isotope is ²²²Rn with a half-life

Half-life

Half-life, abbreviated t½, is the period of time it takes for the amount of a substance undergoing decay to decrease by half. The name was originally used to describe a characteristic of unstable atoms , but it may apply to any quantity which follows a set-rate decay.The original term, dating to...

 of 3.823 days. Four isotopes, ^{218, 219, 220, 222}Rn occur in trace quantities in nature as decay product

Decay product

In nuclear physics, a decay product is the remaining nuclide left over from radioactive decay. Radioactive decay often involves a sequence of steps...

s of, respectively, ²¹⁸At, ²²³Ra, ²²⁴Ra, and ²²⁶Ra. ²¹⁸Rn and ²²²Rn are intermediate steps in the decay chain for ²³⁸U

Uranium-238

Uranium-238 is the most common isotope of uranium found in nature. It is not fissile, but is a fertile material: it can capture a slow neutron and after two beta decays become fissile plutonium-239...

, ²¹⁹Rn is an intermediate step in the decay chain for ²³⁵U

Uranium-235

- References :* .* DOE Fundamentals handbook: Nuclear Physics and Reactor theory , .* A piece of U-235 the size of a grain of rice can produce energy equal to that contained in three tons of coal or fourteen barrels of oil. -External links:* * * one of the earliest articles on U-235 for the...

 and ²²⁰Rn occurs in the decay chain for ²³²Th

Isotopes of thorium

Although thorium has 6 naturally occurring isotopes, none of these isotopes are stable; however, one isotope, 232Th, is relatively stable, with a half-life of 14.05 billion years, considerably longer than the age of the earth, and even slightly longer than the generally-accepted age of the...

.

Table

nuclide symbol	historic name	Z(p Proton The proton is a subatomic particle with the symbol or and a positive electric charge of 1 elementary charge. One or more protons are present in the nucleus of each atom, along with neutrons. The number of protons in each atom is its atomic number.... )	N(n Neutron The neutron is a subatomic hadron particle which has the symbol or , no net electric charge and a mass slightly larger than that of a proton. With the exception of hydrogen, nuclei of atoms consist of protons and neutrons, which are therefore collectively referred to as nucleons. The number of... )	isotopic mass (u)	half-life	decay mode(s)Abbreviations: IT: Isomeric transition Isomeric transition An isomeric transition is a radioactive decay process that involves emission of a gamma ray from an atom where the nucleus is in an excited metastable state, referred to in its excited state, as a nuclear isomer....	daughter isotope(s)	nuclear spin	representative isotopic composition (mole fraction)	range of natural variation (mole fraction)
		excitation energy
195Rn		86	109	195.00544(5)	6 ms			3/2-#
195mRn		50(50) keV			6 ms			13/2+#
196Rn		86	110	196.002115(16)	4.7(11) ms [4.4(+13-9) ms]	α Alpha decay Alpha decay is a type of radioactive decay in which an atomic nucleus emits an alpha particle and thereby transforms into an atom with a mass number 4 less and atomic number 2 less...	192Po	0+
						β+ Beta decay In nuclear physics, beta decay is a type of radioactive decay in which a beta particle is emitted from an atom. There are two types of beta decay: beta minus and beta plus. In the case of beta decay that produces an electron emission, it is referred to as beta minus , while in the case of a...  (rare)	196At
197Rn		86	111	197.00158(7)	66(16) ms [65(+25-14) ms]	α	193Po	3/2-#
						β+ (rare)	197At
197mRn		200(60)# keV			21(5) ms [19(+8-4) ms]	α	193Po	(13/2+)
						β+ (rare)	197At
198Rn		86	112	197.998679(14)	65(3) ms	α (99%)	194Po	0+
						β+ (1%)	198At
199Rn		86	113	198.99837(7)	620(30) ms	α (94%)	195Po	3/2-#
						β+ (6%)	199At
199mRn		180(70) keV			320(20) ms	α (97%)	195Po	13/2+#
						β+ (3%)	199At
200Rn		86	114	199.995699(14)	0.96(3) s	α (98%)	196Po	0+
						β+ (2%)	200At
201Rn		86	115	200.99563(8)	7.0(4) s	α (80%)	197Po	(3/2-)
						β+ (20%)	201At
201mRn		280(90)# keV			3.8(1) s	α (90%)	197Po	(13/2+)
						β+ (10%)	201At
						IT Isomeric transition An isomeric transition is a radioactive decay process that involves emission of a gamma ray from an atom where the nucleus is in an excited metastable state, referred to in its excited state, as a nuclear isomer....  (<1%)	201Rn
202Rn		86	116	201.993263(19)	9.94(18) s	α (85%)	198Po	0+
						β+ (15%)	202At
203Rn		86	117	202.993387(25)	44.2(16) s	α (66%)	199Po	(3/2-)
						β+ (34%)	203At
203mRn		363(4) keV			26.7(5) s	α (80%)	199Po	13/2(+)
						β+ (20%)	203At
204Rn		86	118	203.991429(16)	1.17(18) min	α (73%)	200Po	0+
						β+ (27%)	204At
205Rn		86	119	204.99172(5)	170(4) s	β+ (77%)	205At	5/2-
						α (23%)	201Po
206Rn		86	120	205.990214(16)	5.67(17) min	α (62%)	202Po	0+
						β+ (38%)	206At
207Rn		86	121	206.990734(28)	9.25(17) min	β+ (79%)	207At	5/2-
						α (21%)	203Po
207mRn		899.0(10) keV			181(18) µs			(13/2+)
208Rn		86	122	207.989642(12)	24.35(14) min	α (62%)	204Po	0+
						β+ (38%)	208At
209Rn		86	123	208.990415(21)	28.5(10) min	β+ (83%)	209At	5/2-
						α (17%)	205Po
209m1Rn		1173.98(13) keV			13.4(13) µs			13/2+
209m2Rn		3636.78(23) keV			3.0(3) µs			(35/2+)
210Rn		86	124	209.989696(9)	2.4(1) h	α (96%)	206Po	0+
						β+ (4%)	210At
210m1Rn		1690(15) keV			644(40) ns			8+#
210m2Rn		3837(15) keV			1.06(5) µs			(17)-
210m3Rn		6493(15) keV			1.04(7) µs			(22)+
211Rn		86	125	210.990601(7)	14.6(2) h	α (72.6%)	207Po	1/2-
						β+ (27.4%)	211At
212Rn		86	126	211.990704(3)	23.9(12) min	α	208Po	0+
						β+β+ (rare)	212Po
213Rn		86	127	212.993883(6)	19.5(1) ms	α	209Po	(9/2+)
214Rn		86	128	213.995363(10)	0.27(2) µs	α	210Po	0+
						β+β+ (rare)	214Po
214mRn		4595.4 keV			245(30) ns			(22+)
215Rn		86	129	214.998745(8)	2.30(10) µs	α	211Po	9/2+
216Rn		86	130	216.000274(8)	45(5) µs	α	212Po	0+
217Rn		86	131	217.003928(5)	0.54(5) ms	α	213Po	9/2+
218Rn		86	132	218.0056013(25)	35(5) ms	α	214Po	0+	TraceIntermediate decay product Decay product In nuclear physics, a decay product is the remaining nuclide left over from radioactive decay. Radioactive decay often involves a sequence of steps...  of 238U Uranium-238 Uranium-238 is the most common isotope of uranium found in nature. It is not fissile, but is a fertile material: it can capture a slow neutron and after two beta decays become fissile plutonium-239...
219Rn	Actinon Actinium emanation	86	133	219.0094802(27)	3.96(1) s	α	215Po	5/2+	TraceIntermediate decay product of 235U Uranium-235 - References :* .* DOE Fundamentals handbook: Nuclear Physics and Reactor theory , .* A piece of U-235 the size of a grain of rice can produce energy equal to that contained in three tons of coal or fourteen barrels of oil. -External links:* * * one of the earliest articles on U-235 for the...
220Rn	Thoron Thorium emanation	86	134	220.0113940(24)	55.6(1) s	α	216Po	0+	TraceIntermediate decay product of 232Th
						β-β- (rare)	220Ra
221Rn		86	135	221.015537(6)	25.7(5) min	β- (78%)	221Fr	7/2(+)
						α (22%)	217Po
222Rn	RadonSource of element's name Radium emanation Emanation Emanon Niton	86	136	222.0175777(25)	3.8235(3) d	α	218Po	0+	Trace
223Rn		86	137	223.02179(32)#	24.3(4) min	β-	223Fr	7/2
224Rn		86	138	224.02409(32)#	107(3) min	β-	224Fr	0+
225Rn		86	139	225.02844(32)#	4.66(4) min	β-	225Fr	7/2-
226Rn		86	140	226.03089(43)#	7.4(1) min	β-	226Fr	0+
227Rn		86	141	227.03541(45)#	20.8(7) s	β-	227Fr	5/2(+#)
228Rn		86	142	228.03799(44)#	65(2) s	β-	228Fr	0+
229Rn		86	143	229.0426536(141)	12 s

The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.