The isotope 206po has a half-life of 8.8 days. if you have 5.68 x 1025 atoms of this isotope, how long will it take for the sample to decay to 3.55 x 1024 atoms?

The normal activity of living carbon-containing matter is found to be about 15 decays per minute for every gram of carbon. This activity arises from the small proportion of radioactive C614C614 present with the stable carbon istope C612. When the organism is dead, its interaction with the atmosphere (which maintains the above equilibrium activity) ceases and its activity begins to drop. From the known half-life (5730 years) of C614, and the measured activity, the age of the specimen can be approximately estimated. This is the principle of  C614 dating used in archaeology.
Suppose a specimen from Mohenjodaro gives an activity of 9 decays per minute per gram of carbon. Estimate the approximate age of the Indus Valley Civilisation.

Given,
Normal activity, R
0

 = 15 decays/min,

Present activity R = 9 decays/min, Half life, T = 5730 years, Age t =? 


As, activity is proportional to the number of radioactive atoms, therefore,

                   NN0 = RR0 = 915 

But,             NN0 = e-λt

∴                e-λt = 915 =35 

                   e+λt = 53

⇒     λt logee = loge53 = 2.3026 log 1.6667

⇒            λt = 2.3026 × 0.2218    = 0.5109∴  t = 0.5109λ 

But, λ = 0.693T =0.6935730 Yr-1

Therefore,

               t =0.51090.693/5730 = 0.5109 × 57300.693

               t = 4224.3 years. is the approximate age.

Alpha particles — The nucleus of a helium atom, made up of two neutrons and two protons with a charge of +2. Certain radioactive nuclei emit alpha particles. Alpha particles generally carry more energy than gamma or beta particles, and deposit that energy very quickly while passing through tissue. Alpha particles can be stopped by a thin layer of light material, such as a sheet of paper, and cannot penetrate the outer, dead layer of skin. Therefore, they do not damage living tissue when outside the body. When alpha-emitting atoms are inhaled or swallowed, however, they are especially damaging because they transfer relatively large amounts of ionizing energy to living cells. See also beta particle, gamma ray, neutron, x-ray.

Atom — The smallest particle of an element that can enter into a chemical reaction.

Beta Particles —  Electrons ejected from the nucleus of a decaying atom. Although they can be stopped by a thin sheet of aluminum, beta particles can penetrate the dead skin layer, potentially causing burns. They can pose a serious direct or external radiation threat and can be lethal depending on the amount received. They also pose a serious internal radiation threat if beta-emitting atoms are ingested or inhaled. See also alpha particle, gamma ray,neutron, x-ray.

Decay Chain (Decay Series) — The series of decays that certain radioisotopes go through before reaching a stable form. For example, the decay chain that begins with uranium-238 (U-238) ends in lead-206 (Pb-206), after forming isotopes, such as uranium-234 (U-234), thorium-230 (Th-230), radium-226 (Ra-226), and radon-222 (Rn-222).

Gamma Rays — High-energy electromagnetic radiation emitted by certain radionuclides when their nuclei transition from a higher to a lower energy state. These rays have high energy and a short wave length. All gamma rays emitted from a given isotope have the same energy, a characteristic that enables scientists to identify which gamma emitters are present in a sample. Gamma rays penetrate tissue farther than do beta or alpha particles, but leave a lower concentration of ions in their path to potentially cause cell damage. Gamma rays are very similar to x-rays. See also neutron.

Isotope — A nuclide of an element having the same number of protons but a different number of neutrons.

Neutron — A small atomic particle possessing no electrical charge typically found within an atom’s nucleus. Neutrons are, as the name implies, neutral in their charge. That is, they have neither a positive nor a negative charge. A neutron has about the same mass as a proton. See also alpha particle, beta particle, gamma ray, nucleon, x-ray.

Radioactive Decay — Disintegration of the nucleus of an unstable atom by the release of radiation.

Radiation — Energy moving in the form of particles or waves. Familiar radiations are heat, light, radio waves, and microwaves. Ionizing radiation is a very high-energy form of electromagnetic radiation.

Radioactive Material — Material that contains unstable (radioactive) atoms that give off radiation as they decay.

Radionuclide — An unstable and therefore radioactive form of a nuclide.

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This list is incomplete; you can help by adding missing items. (April 2011)

This is a list of radioactive nuclides (sometimes also called isotopes), ordered by half-life from shortest to longest, in seconds, minutes, hours, days, and years. Current methods make it difficult to measure half-lives between approximately 10−19 and 10−10 seconds.[1]

isotope half-life
10−24 seconds
5
H
86(6)
4
Li
91(9)
4
H
139(10)
10
N
143(36)
11
O
198(12)
10
He
260(40)
6
H
294(67)
5
Li
370(30)
14
F
500(60)
7
B
570(14)
11
N
585(7)
5
He
602(22)
16
Be
650(130)
7
H
652(558)
11m
N
690(80)
21
B
> 760
15
Ne
770(300)
15
Be
790(270)
20
B
> 912.4

23 yoctoseconds is the time needed to traverse a 7 femtometre distance at the speed of light, around the diameter of a large atomic nucleus.

isotope half-life
10−21 seconds
fluorine-15 1.11
oxygen-12 1.14
sodium-18 1.34
lithium-10m2 1.35
helium-10 1.52
lithium-10 2
carbon-8 2
beryllium-13 2.7
helium-7 2.51
lithium-13 3.3
lithium-10m1 3.7
neon-16 3.74
beryllium-6 5
helium-9 7
fluorine-16 11
boron-9 845
isotope half-life
10−18 seconds
beryllium-9m 1.25
beryllium-8 81.9
isotope half-life
10−15 seconds
oxygen-27 1.75
isotope half-life
10−12 seconds
boron-16 ≤190
isotope half-life
10−9 seconds
lithium-12 <10
boron-18 26
carbon-21 30
fluorine-28 40
oxygen-26 40
sodium-19 40
oxygen-25 50
nitrogen-24 52
protactinium-219 53
neon-34 60
sodium-37 60
protactinium-220m2 69
actinium-217 69
francium-215 86
lead-196m1 <100
uranium-236m1 100
bismuth-199m2 100
oxygen-28 100
curium-247m2 100.6
actinium-218m 103
francium-214m2 103
bismuth-201m3 105
lead-202m3 107
francium-214m3 108
thorium-218 109
lead-202m2 110
neptunium-238m 112
polonium-205m4 115
bismuth-201m2 118
uranium-236m2 120
lead-203m3 122
bismuth-201m4 124
astatine-213 125
lead-193m2 135
lead-198m2 137
lead-196m3 140
lead-190m1 150
thallium-198m2 150
americium-239m 163
lead-192m1 164
bismuth-199m3 168
neon-33 180
sodium-36 180
curium-242m 180
radium-216 182
plutonium-239m1 193
bismuth-203m2 194
polonium-198m1 200
polonium-202m >200
polonium-203m2 >200
lead-210m 201
lead-206m2 202
bismuth-197m2 204
polonium-207m1 205
bismuth-197m5 209
lead-198m3 212
lead-205m3 217
polonium-206m1 222
beryllium-12m 233
thallium-205m2 235
polonium-211m2 243
radon-214m 245
fluorine-31 250
uranium-239m1 >250
bismuth-197m4 253
fluorine-30 260
nitrogen-25 260
polonium-210m 263
bismuth-197m3 263
lead-204m1 265
astatine-214m1 265
radium-208m 270
lead-196m4 270
radon-214 270
uranium-238m 280
curium-245m 290
thallium-192m2 296
polonium-212 299
protactinium-220m1 308
bismuth-202m2 310
polonium-205m1 310
plutonium-243m 330
thallium-200m2 330
neptunium-222 380
lead-216m 400
astatine-206m 410
protactinium-229m 420
lead-204m3 450
lead-208m 500
bismuth-190m2 >500
curium-244m2 >500
lead-201m2 508
radium-215m3 555
astatine-214 558
berkelium-242m 600
thorium-216m2 615
radon-210m1 644
uranium-221 660
francium-216 700
actinium-217m 740
bismuth-195m2 750
polonium-198m2 750
lead-192m3 756
astatine-214m2 760
protactinium-220 780
uranium-239m2 780
lead-188m2 797
lead-188m1 830
radium-212m2 850
polonium-196m 850
bismuth-189m2 880
plutonium-241m1 880
isotope half-life
10−6 seconds
lead-196m2 <1
polonium-192m ~1
radon-210m3 1.04
thorium-219 1.05
polonium-206m2 1.05
radon-210m2 1.06
curium-243m 1.08
actinium-218 1.08
lead-192m2 1.1
plutonium-237m2 1.1
lead-197m2 1.15
americium-241m 1.2
radium-215m2 1.39
bismuth-211m 1.4
uranium-222 1.4
radium-217 1.63
neptunium-223 2.15
radium-210m 2.24
radon-215 2.30
bismuth-217m 2.70
polonium-211m3 2.8
radon-209m2 3.0
bismuth-202m1 3.04
polonium-213 3.65
lead-198m1 4.19
protactinium-221 4.9
astatine-210m2 5.66
nobelium-250 5.7
lead-212m 6.0
lead-214m 6.2
bismuth-187m2 7
thorium-229m 7
radium-215m1 7.1
lead-190m3 7.2
plutonium-239m2 7.5
bismuth-206m1 7.7
astatine-205m 7.76
thorium-220 9.7
lead-195m2 10.0
lead-199m2 10.1
radium-212m1 10.9
astatine-196m2 11
actinium-219 11.8
radon-209m1 13.4
polonium-194m 15
francium-217 16.8
uranium-223 21
plutonium-241m2 21
fermium-251m 21.1
curium-249m 23
rutherfordium-254 23
lead-205m1 24.2
neptunium-220 25
lead-190m2 25
radium-218 25.2
lead-189m2 26
curium-247m1 26.3
berkelium-250m1 29
nobelium-253m 31
polonium-186 34
americium-238m 35
nobelium-250m 36
neptunium-224 38
californium-249m 45
radon-216 45
rutherfordium-253 48
bismuth-185m 49
polonium-207m2 49
radium-231m ~53
uranium-219 55
berkelium-251m 58
americium-246m2 73
seaborgium-261m 92
astatine-215 100
astatine-216m 100
protactinium-218 113
lead-206m1 125
thorium-216m1 137
curium-248m 146
neptunium-219 150
astatine-212m2 152
polonium-214 164.3
radon-207m 181
bismuth-207m 182
darmstadtium-270 205
berkelium-250m2 213
darmstadtium-269 230
lead-178 230
copernicium-277 240
thorium-217 240
darmstadtium-273 240
berkelium-249m 300
astatine-216 300
bismuth-187m1 320
nihonium-278 340
hassium-265m 360
fermium-258 370
polonium-188 430
actinium-216 440
actinium-216m 443
astatine-210m1 482
polonium-187m 500
hassium-264 540
radon-217 540
polonium-205m2 645
copernicium-277 690
oganesson-294 690
fermium-241 730
hassium-263 760
fermium-242 800
bismuth-206m2 890
mendelevium-245 900
copernicium-282 910
uranium-224 940
isotope half-life
10−3 seconds
francium-218 1.0
bismuth-204m2 1.07
protactinium-217m 1.08
meitnerium-266 1.2
nobelium-258 1.2
uranium-216m 1.31
polonium-187 1.40
nihonium-278 1.4
sodium-35 1.5
radium-215 1.55
darmstadtium-271m 1.7
astatine-191 1.7
thorium-208 1.7
thorium-221 1.73
polonium-215 1.781
hassium-265 1.96
bismuth-185 2
roentgenium-272 2
astatine-191m 2.1
radium-213m 2.1
thorium-222 2.237
uranium-215 2.24
polonium-190 2.46
fluorine-29 2.5
flerovium-284 2.5
bismuth-208m 2.58
radium-202 2.6
boron-19 2.92
seaborgium-258 3
hassium-266 3.02
fermium-244 3.12
protactinium-222 3.2
francium-214m1 3.35
neon-31 3.4
protactinium-217 3.48
neon-32 3.5
darmstadtium-277 3.5
protactinium-211 3.8
lead-179 3.9
roentgenium-278 4
radium-203 4
seaborgium-260 4
uranium-216 4.3
beryllium-14 4.35
lead-180 4.5
radon-196 4.7
fluorine-27 5
bismuth-189m1 5.0
francium-214 5.0
meitnerium-277 5
nobelium-262 5
polonium-189 5
boron-17 5.08
protactinium-223 5.1
americium-223 5.2
sodium-34 5.5
lead-205m2 5.55
neptunium-225 6
uranium-218 6
radon-195 6
radon-195m 6
carbon-22 6.2
meitnerium-270 6.3
rutherfordium-256 6.4
bismuth-184 6.6
thorium-209 7
protactinium-213 7
seaborgium-262 7
neon-30 7.3
protactinium-212 8
sodium-33 8
livermorium-290 8.3
oxygen-13 8.58
lithium-11 8.59
fluorine-26 9.6
bohrium-262m 9.6
bismuth-186m 9.8
boron-15 9.87
darmstadtium-270m 10
radium-219 10
hassium-277 11
nitrogen-12 11
astatine-192 11.5
bohrium-261 11.8
roentgenium-274 12
boron-14 12.5
bismuth-204m1 13.0
livermorium-292 13
bismuth-184m 13
sodium-32 13.2
americium-242m2 14.0
protactinium-215 14
nitrogen-23 14.5
rutherfordium-258 14.7
bismuth-186 14.8
neon-29 14.8
actinium-206m1 15
carbon-20 16
francium-199 16
protactinium-214 17
sodium-31 17
thorium-210 17
boron-13 17.33
radium-220 17.9
neon-28 18.9
livermorium-291 19
radon-213 19.5
actinium-205 20
astatine-196m1 20
rutherfordium-270 20
francium-219 20
meitnerium-275 20
boron-12 20.2
radon-197m 21
rutherfordium-260 21
astatine-193m1 21
californium-238 21.1
beryllium-12 21.49
francium-218m1 22.0
tennessine-293 22
polonium-191 22
francium-200 24
nitrogen-22 24
actinium-206 25
uranium-217 26
actinium-220 26.36
thorium-216 26.8
meitnerium-268 27
astatine-193m2 27
lawrencium-251 27
actinium-208m 28
astatine-193 28
sodium-28 30.5
actinium-207 31
neon-27 32
bismuth-187 32
polonium-192 32.2
astatine-217 32.3
uranium-234m 33.5
curium-244m1 34
bohrium-260 35
radon-218 35
neptunium-226 35
thorium-212 36
moscovium-287 37
seaborgium-264 37
dubnium-255 37
actinium-206m2 41
radium-203m 41
bismuth-188 44
sodium-29 44.9
lead-181 45
carbon-19 46.2
thorium-211 48
sodium-30 48.4
fluorine-25 50
tennessine-294 51
actinium-221 52
hassium-267 55
radium-207m 57
livermorium-293 57
polonium-205m3 57.4
radium-204 60
lead-182 60
uranium-225 61
oxygen-24 65
radon-198 65
radon-197 66
francium-201 67
nihonium-282 73
nihonium-283 75
oxygen-23 82
bohrium-262 84
nitrogen-21 87
astatine-192m 88
darmstadtium-271 90
roentgenium-279 90
carbon-18 92
actinium-209 92
polonium-191m 93
actinium-208 97
copernicium-284 98
thorium-214 100
flerovium-285 100
protactinium-216 105
nobelium-260 106
astatine-204m 108
astatine-212m1 119
helium-8 119
flerovium-286 120
seaborgium-263m 120
bismuth-191m 124
carbon-9 126.5
nitrogen-20 130
thorium-213 140
polonium-216 145
astatine-195m 147
moscovium-288 164
actinium-215 170
lithium-9 178.3
copernicium-281 180
radium-205m 180
plutonium-237m1 180
neon-26 192
carbon-17 193
mendelevium-247m 200
seaborgium-261 200
darmstadtium-279 210
actinium-211 213
bismuth-188m 220
radium-205 220
fermium-243 231
polonium-193m 240
radium-206 240
astatine-196 253
uranium-226 269
nitrogen-19 271
hassium-266m 280
nobelium-254m 280
astatine-194 286
hassium-275 290
francium-202 290
sodium-27 301
bismuth-203m1 303
astatine-212 314
radon-199m 320
astatine-194m 323
astatine-195 328
moscovium-289 330
francium-202m 340
actinium-210 350
seaborgium-266 360
astatine-197 390
fluorine-24 390
lawrencium-252 390
polonium-194 392
bismuth-200m2 400
mendelevium-245m 400
mendelevium-244 400
lead-183m 415
polonium-193 420
meitnerium-274 440
sodium-20 447.9
meitnerium-276 450
astatine-202m2 460
flerovium-287 480
lead-203m2 480
lead-184 490
hassium-273 510
neptunium-227 510
dubnium-259 510
polonium-211 516
lead-183 535
francium-203 550
lawrencium-253 580
thorium-223 600
bismuth-196m1 600
seaborgium-259 600
neon-25 602
radon-199 620
nitrogen-18 622
lawrencium-257 646
moscovium-290 650
francium-200m 650
flerovium-288 660
dubnium-257m 670
bismuth-189 674
francium-206m2 700
actinium-213 731
carbon-16 747
boron-8 770
nobelium-251 780
lead-207m 806
helium-6 806.7
lithium-8 839.9
protactinium-224 844
bohrium-265 900
bohrium-266 900
lutetium-153 900
nihonium-284 910
actinium-212 920
radon-200 960
bohrium-264 970
isotope half-life
seconds minutes seconds
seaborgium-263 1
astatine-198m 1.0
mendelevium-246 1.0
thorium-224 1.05
sodium-26 1.077
plutonium-228 1.1
mendelevium-247 1.12
curium-246m 1.12
bohrium-271 1.2
thorium-215 1.2
radium-208 1.3
radium-207 1.3
rutherfordium-268 1.4
hassium-268 1.42
polonium-217 1.47
astatine-218 1.5
lawrencium-253m 1.5
fermium-259 1.5
dubnium-260 1.52
dubnium-257 1.53
fermium-246 1.54
neon-18 1.672
francium-204 1.7
francium-204m2 1.7
nobelium-251m 1.7
protactinium-225 1.7
americium-229 1.8
flerovium-289 1.9
dubnium-256 1.9
mendelevium-249m 1.9
dubnium-258m 1.9
polonium-195m 1.92
fermium-250m 1.92
astatine-197m 2.0
californium-237 2.1
fluorine-23 2.23
oxygen-22 2.25
nobelium-252 2.27
rutherfordium-255 2.3
rutherfordium-262 2.3
carbon-15 2.449
radium-214 2.46
rutherfordium-259m 2.5
francium-204m1 2.6
flerovium-289 2.6
radium-213 2.74
polonium-207m3 2.79
nobelium-256 2.91
bismuth-193m 3.2
rutherfordium-259 3.2
oxygen-21 3.42
astatine-200m2 3.5
radium-210 3.7
francium-205 3.80
radon-201m 3.8
radon-219 3.96
rutherfordium-261m 4
lead-185m 4.07
rutherfordium-257m 4.1
lawrencium-258 4.1
fluorine-21 4.158
nitrogen-17 4.173
copernicium-283 4.2
astatine-198 4.2
nihonium-285 4.2
fermium-245 4.2
fluorine-22 4.23
meitnerium-278 4.5
dubnium-258 4.5
dubnium-261 4.5
roentgenium-280 4.6
radium-209 4.6
polonium-195 4.64
rutherfordium-257 4.7
lead-186 4.82
actinium-222 5.0
francium-232 5
polonium-196 5.56
einsteinium-240 6
lawrencium-259 6.2
bismuth-190m1 6.2
lead-203m1 6.21
bismuth-190 6.3
lead-185 6.3
astatine-199 6.92
radon-201 7.0
mendelevium-248 7
nitrogen-16 7.13
bismuth-198m2 7.7
seaborgium-265 8
actinium-214 8.2
bismuth-219 8.7
hassium-270 9
bismuth-220 9.5
nihonium-286 9.5
bohrium-272 9.8
radon-202 9.94
hassium-271 10
einsteinium-241 10
fluorine-20 11.07
radon-229 12
bismuth-191 12.3
darmstadtium-281 12.7
radium-212 13.0
radium-211 13
lawrencium-254 13
einsteinium-242 13.5
oxygen-20 13.51
beryllium-11 13.81
francium-207 14.8
lead-218 15
lead-187 15.2
francium-206m1 15.9
francium-206 16
hassium-269 16
seaborgium-265m 16.2
bohrium-267 17
roentgenium-281 17
neon-19 17.22
francium-231 17.6
lead-187m 18.3
berkelium-234 19
francium-230 19.1
carbon-10 19.29
lead-217 20
radon-227 20.8
einsteinium-243 21
berkelium-233 21
berkelium-236 22
lawrencium-255 22
sodium-21 22.49
rutherfordium-266 23
mendelevium-249 24
nobelium-257 25
polonium-211m1 25.2
lead-188 25.5
polonium-197m 25.8
oxygen-19 26.464
radon-203m 26.7
curium-233 27
lawrencium-256 27
francium-220 27.4
copernicium-285 28
radium-221 28
dubnium-263 29
radium-234 30
radium-233 30
fermium-247 31
americium-230 32
bismuth-218 33
bismuth-192 34.6
francium-213 34.6
dubnium-262 35
fermium-248 35.1
bismuth-215m 36.9
einsteinium-244 37
neon-23 37.24
radium-222 38.0
francium-228 38
bismuth-192m 39.6
polonium-220 40
bohrium-274 40
astatine-200 43.2
actinium-234 44
radon-203 44.2
polonium-203m1 45
polonium-212m 45.1
astatine-200m1 47
francium-226 49
francium-209 50.0
astatine-223 50
francium-229 50.2
lead-189m1 50.5
nobelium-254 51
lead-189 51
curium-234 52
mendelevium-250 52
polonium-197 53.6
astatine-222 54
radon-220 55.6
astatine-219 56
francium-208 59.1
sodium-25 59.1
californium-239 1.0 60
actinium-235 1.0 60
lead-201m1 1.02 61
bohrium-270 1.02 61
neptunium-228 1.023 61.4
actinium-222m 1.05 63
californium-240 1.06 64
fluorine-17 1.0748 64.49
radon-228 1.08 65
rutherfordium-263 1.1 66
uranium-227 1.1 66
einsteinium-245 1.1 66
bismuth-193 1.12 67
radon-204 1.17 70
protactinium-234m 1.17 70
oxygen-14 1.1770 70.62
lead-190 1.18 71
actinium-236 1.20 72
rutherfordium-261 1.30 78
americium-232 1.32 79
lead-191 1.33 80
seaborgium-267 1.4 84
astatine-201 1.42 85
bismuth-195m1 1.45 87
bismuth-194 1.58 95
fermium-249 1.6 96
nobelium-253 1.62 97
bismuth-217 1.642 98.5
lead-216 1.65 99
roentgenium-282 1.7 100
plutonium-230 1.70 102
radium-231 1.72 103
polonium-198 1.77 106
protactinium-226 1.8 110
berkelium-252 1.8 110
neptunium-243 1.85 111
bismuth-194m2 1.92 115
actinium-232 1.98 119
protactinium-240 2 120
plutonium-229 2.0 120
actinium-230 2.03 122
oxygen-15 2.0373 122.24
bismuth-194m1 2.08 125
actinium-223 2.10 126
bismuth-211 2.14 128
bismuth-216 2.17 130
lead-191m 2.18 131
polonium-221 2.2 130
neptunium-242 2.2 130
protactinium-238 2.27 136
neptunium-244 2.29 137
mendelevium-252 2.30 138
astatine-221 2.3 140
americium-234 2.32 139
lead-215 2.34 140
berkelium-238 2.40 144
seaborgium-271 2.4 140
actinium-233 2.42 145
francium-227 2.47 148
astatine-224 2.5 150
lawrencium-260 2.7 160
radon-205 2.8 170
astatine-202m1 3.03 182
bismuth-195 3.05 183
astatine-202 3.07 184
polonium-218 3.10 186
francium-211 3.10 186
nobelium-255 3.1 190
francium-210 3.18 191
americium-233 3.2 190
francium-224 3.33 200
neon-24 3.38 203
californium-242 3.49 209
lead-192 3.5 210
americium-236 3.6 220
astatine-220 3.71 223
californium-241 3.78 227
radium-229 4.0 240
mendelevium-251 4.0 240
francium-225 4.0 240
neptunium-229 4.0 240
bismuth-196m2 4.00 240
radium-232 4.2 250
polonium-199m 4.17 250
einsteinium-247 4.55 273
berkelium-241 4.6 280
neptunium-230 4.6 280
radon-225 4.66 280
berkelium-240 4.8 290
thorium-237 4.8 290
francium-221 4.9 290
curium-235 5 300
lead-193 5 300
bismuth-197m1 5.04 302
bismuth-196 5.1 310
polonium-199 5.48 329
neptunium-242m 5.5 330
radon-206 5.67 340
lead-193m1 5.8 350
bismuth-216m 6.6 400
curium-236 6.8 410
berkelium-242 7.0 420
bismuth-212m2 7.0 420
thorium-235 7.2 430
neptunium-240m 7.22 433
astatine-203 7.37 442
radon-226 7.4 440
actinium-231 7.5 450
bismuth-215 7.6 460
einsteinium-246 7.7 460
lead-197 8.1 490
plutonium-231 8.6 520
protactinium-237 8.7 520
thorium-225 8.72 523
polonium-201m 8.9 530
protactinium-236 9.1 550
polonium-222 9.1 550
uranium-228 9.1 550
astatine-204 9.2 550
radon-207 9.25 555
bismuth-197 9.33 560
thorium-238 9.4 560
copper-62 9.673 580.4
americium-235 9.9 590
nitrogen-13 9.965 597.9
berkelium-253 10 600
mercury-210[2] 10 600
mendelevium-254 10 600
lead-213 10.2 610
bismuth-198 10.3 620
polonium-219 10.3 620
californium-243 10.7 640
polonium-200 11.5 690
bismuth-198m1 11.6 700
lead-194 12.0 720
mendelevium-253 12 720
lead-199m1 12.2 730
californium-256 12.3 740
neptunium-241 13.9 830
seaborgium-269 14 840
francium-222 14.2 850
[free] neutron, 1
0
n
14.692 881.5
neptunium-232 14.7 880
lead-195m1 15.0 900
rutherfordium-263 15 900
lead-195 ~15 ~900
polonium-201 15.3 920
isotope half-life minutes 103 seconds hours 103 seconds days 103 seconds
curium-251 16.8 1.01
uranium-242 16.8 1.01
californium-244 19.4 1.16
bismuth-214 19.9 1.19
francium-212 20.0 1.20
curium-237 20 1.2
carbon-11 20.334 1.2200
plutonium-233 20.9 1.25
thorium-233 21.83 1.310
francium-223 22.00 1.320
americium-247 23.0 1.38
uranium-239 23.45 1.407
radon-212 23.9 1.43
radon-223 24.3 1.46
radon-208 24.35 1.461
protactinium-235 24.44 1.466
bismuth-199m1 24.70 1.482
bismuth-212m1 25.0 1.50
americium-246m1 25.0 1.50
plutonium-235 25.3 1.52
einsteinium-256 25.4 1.52
radon-221 25.7 1.54
americium-244m 26 1.6
uranium-235m 26 1.6
astatine-205 26.2 1.57
lead-214 26.8 1.61
mendelevium-255 27 1.6
bismuth-199 27 1.6
einsteinium-248 27 1.6
mendelevium-254m 28 1.7
radon-209 28.5 1.71
fermium-250 30.4 1.82
thorium-226 30.57 1.834
astatine-206 30.6 1.84
bismuth-200m1 31 1.9
plutonium-232 33.7 2.02
lead-211 36.1 2.17
neptunium-233 36.2 2.17
bismuth-200 36.4 2.18
polonium-203 36.7 2.20
lead-196 37 2.2
thorium-236 37.5 2.25
protactinium-227 38.3 2.30
americium-246 39 2.3
radium-227 42.2 2.53
lead-197m1 42.9 2.57
lawrencium-261 44 2.6
polonium-202 44.7 2.68
californium-245 45.0 2.70
bismuth-213 45.59 2.735
neptunium-231 48.8 2.93
berkelium-251 55.6 3.34
mendelevium-258m 57.0 3.42
uranium-229 58 3.5
nobelium-259 58 3.5
bismuth-201m1 59.1 3.55
dubnium-270 1.0 3.6
bismuth-212 1.0092 3.633
neptunium-240 1.032 3.72
actinium-229 1.045 3.76
curium-249 1.0692 3.849
lead-204m2 1.12 4.0
gallium-68 1.1285 4.063
americium-237 1.22 4.4
mendelevium-256 1.283 4.62
rutherfordium-267 1.3 4.7
dubnium-266 1.33 4.8
californium-255 1.417 5.10
lead-199 1.50 5.4
radium-230 1.55 5.6
mendelevium-259 1.60 5.8
americium-238 1.63 5.9
astatine-208 1.63 5.9
polonium-205 1.66 6.0
einsteinium-249 1.703 6.13
bismuth-202 1.72 6.2
astatine-207 1.80 6.5
bismuth-201 1.80 6.5
protactinium-239 1.8 6.5
fluorine-18 1.8295 6.586
americium-245 2.05 7.4
einsteinium-250m 2.22 8.0
radon-210 2.4 8.6
lead-198 2.4 8.6
curium-238 2.4 8.6
curium-239 2.5 9.0
fermium-256 2.627 9.46
actinium-224 2.78 10.0
californium-247 3.11 11.2
berkelium-250 3.212 11.56
fermium-254 3.240 11.66
lead-209 3.253 11.71
lead-202m1 3.53 12.7
polonium-204 3.53 12.7
lawrencium-262 3.6 13
berkelium-244 4.35 15.7
berkelium-243 4.5 16
dubnium-267 4.6 17
plutonium-243 4.956 17.84
fermium-251 5.30 19.1
polonium-207 5.80 20.9
astatine-209 5.41 19.5
mendelevium-257 5.52 19.9
actinium-228 6.13 22.1
protactinium-234 6.70 24.1
astatine-211 7.214 25.97
einsteinium-256m 7.6 27
astatine-210 8.1 29
einsteinium-250 8.6 31
plutonium-234 8.8 32
lead-201 9.33 33.6
americium-244 10.1 36
erbium-165 10.36 37.3
plutonium-245 10.5 38
lead-212 10.64 38.3
lawrencium-266 11 40
bismuth-204 11.22 40.4
bismuth-203 11.76 42.3
americium-239 11.9 43
uranium-240 14.1 51
radon-211 14.6 53
sodium-24 14.96 53.9
americium-242 16.02 57.7
fermium-255 20.07 72.3
lead-200 21.5 77
protactinium-228 22 79
neptunium-236m 22.5 81
berkelium-248m 23.7 85
fermium-252 1.058 91.4
thorium-231 1.0634 91.88
dubnium-268 1.283 110.9
erbium-160 1.191 102.9
actinium-226 1.2238 105.74
protactinium-232 1.31 113
einsteinium-251 1.375 118.8
californium-246 1.4875 128.52
protactinium-229 1.50 130
einsteinium-255 1.6375 141.48
berkelium-246 1.80 156
neptunium-238 2.117 182.9
americium-240 2.117 182.9
lead-203 2.16138 186.743
plutonium-247 2.27 196
neptunium-239 2.356 203.6
gold-198 2.695 232.8
fermium-253 3.00 259
gold-199 3.169 273.8
radium-224 3.6319 313.80
radon-222 3.8235 330.35
uranium-231 4.2 360
neptunium-234 4.4 380
calcium-47 4.536 391.9
berkelium-245 4.94 427
bismuth-210 5.012 433.0
manganese-52 5.591 483.1
gold-196 6.183 534.2
bismuth-206 6.243 539.4
uranium-237 6.75 583
einsteinium-257 7.7 670
iodine-131 8.02 693
polonium-206 8.8 760
thulium-167 9.25 799
actinium-225 10.0 860
plutonium-246 10.84 937
radium-223 11.43 988
isotope half-life days 106 seconds years 106 seconds
phosphorus-32 14.29 1.235
radium-225 14.9 1.29
bismuth-205 15.31 1.323
vanadium-48 15.9735 1.38011
protactinium-230 17.4 1.50
californium-253 17.81 1.539
thorium-227 18.68 1.614
einsteinium-253 20.47 1.769
uranium-230 20.8 1.80
thorium-234 24.10 2.082
protactinium-233 26.975 2.3306
curium-240 27 2.3
chromium-51 27.7025 2.39350
mendelevium-260 27.8 2.40
curium-241 32.8 2.83
einsteinium-255 39.8 3.44
plutonium-237 45.2 3.91
mendelevium-258 51.5 4.45
beryllium-7 53.12 4.590
californium-254 60.5 5.23
cobalt-56 77.27 6.676
scandium-46 83.79 7.239
sulfur-35 87.32 7.544
thulium-168 93.1 8.04
fermium-257 100.5 8.68
thulium-170 128.6 11.11
polonium-210 138.376 11.9557
calcium-45 162.7 14.06
curium-242 162.8 14.07
gold-195 186.1 16.08
zinc-65 243.7 21.06
cobalt-57 271.79 23.483
einsteinium-254 275.7 23.82
vanadium-49 330 29
berkelium-249 330 29
californium-248 333.5 28.81
ruthenium-106 1.023 32.3
neptunium-235 1.0845 34.22
cadmium-109 1.267 40.0
einsteinium-252 1.2915 40.76
thorium-228 1.9116 60.33
thulium-171 1.92 61
caesium-134 2.0652 65.17
sodium-22 2.602 82.1
californium-252 2.645 83.5
iron-55 2.756 87.0
plutonium-236 2.858 90.2
polonium-208 2.898 0.2504
rhodium-101 3.3 100
cobalt-60 5.2714 166.35
radium-228 5.75 181
krypton-85 10.756 339.4
hydrogen-3
(also known as tritium)
12.32 389
californium-250 13.08 413
plutonium-241 14.290 451.0
niobium-93m 16.13 509
curium-244 18.10 571
actinium-227 21.772 687.1
lead-210 22.3 700
strontium-90 28.79 909
curium-243 29.1 920
caesium-137 30.17 952
isotope half-life years 109 seconds
bismuth-207 32.9 1.04
titanium-44 63 2.0
uranium-232 68.9 2.17
plutonium-238 87.7 2.77
samarium-151 96.6 3.05
nickel-63 100.1 3.16
polonium-209 125.2 3.95
americium-242m1 141 4.4
silicon-32 170 5.4
argon-39 269 8.5
berkelium-248 >300 >9.5
californium-249 351 11.1
silver-108m 418 13.2
americium-241 432.2 13.64
mercury-194 444 14.0
niobium-91 680 21
californium-251 900 28
holmium-166m1 1,200 38
berkelium-247 1,380 44
radium-226 1,600 50
molybdenum-93 4,000 130
holmium-163 4,570 144
curium-246 4,760 150
carbon-14[3] 5,730 181
plutonium-240 6,561 207.0
thorium-229 7,340 232
americium-243 7,370 233
curium-250 8,300 260
curium-245 8,500 270
niobium-94 20,300 640
plutonium-239 24,110 761
isotope half-life millennia 1012 seconds 106 years 1012 seconds
protactinium-231 32.76 1.034
lead-202 52.5 1.66
lanthanum-137 60 1.9
thorium-230 75.38 2.379
nickel-59 76 2.4
calcium-41 103 3.3
neptunium-236 154 4.9
uranium-233 159.2 5.02
rhenium-186m 200 6.3
technetium-99 211.1 6.66
krypton-81 229 7.2
tin-126 230 7.3
uranium-234 245.5 7.75
chlorine-36 301 9.5
selenium-79 327 10.3
curium-248 348 11.0
bismuth-208 368 11.6
plutonium-242 375 11.8
aluminium-26 717 22.6
beryllium-10 1.39 44
zirconium-93 1.53 48
gadolinium-150 1.79 56
neptunium-237 2.144 67.7
caesium-135 2.3 73
iron-60 2.6 82
technetium-97 2.6 82
dysprosium-154 3.0 95
bismuth-210m 3.04 96
manganese-53 3.7 120
technetium-98 4.2 130
palladium-107 6.5 210
hafnium-182 8.9 280
lead-205 17.3 550
curium-247 15.6 490
iodine-129 15.7 500
uranium-236 23.42 739
isotope half-life 106 years 1015 seconds 109 years 1015 seconds
niobium-92 34.7 1.10
samarium-146 68 2.1
plutonium-244 80 2.5
uranium-235 703.8 22.21
potassium-40 1.251 39.5
uranium-238 4.468 141.0
thorium-232 14.05 443
isotope half-life 109 years 1018 seconds
lutetium-176 37.64 1.188
rhenium-187 41.22 1.301
rubidium-87 49.72 1.569
lanthanum-138 102.1 3.22
samarium-147 106.1 3.35
platinum-190 650 21
isotope half-life 1012 years 1021 seconds 1015 years 1021 seconds
gadolinium-152 110 3.5
indium-115 440 14
hafnium-174 2.002 63.2
osmium-186 2.002 63.2
neodymium-144 2.292 72.3
samarium-148 7.005 221.1
cadmium-113 7.7 240
isotope half-life 1015 years 1024 seconds 1018 years 1024 seconds
vanadium-50 140 4.4
tungsten-180 1.801 56.8
europium-151 5.004 157.9
molybdenum-100 7.804 246.3
neodymium-150 7.905 249.5
tellurium-130 8.806 277.9
zirconium-96 20 630
bismuth-209 20.1 630
calcium-48 23.01 726
cadmium-116 31.02 979
isotope half-life 1018 years 1027 seconds 1021 years 1027 seconds
selenium-82 110 3.5
barium-130 1.2 38
germanium-76 1.8 57
xenon-136 2.165 68.3
krypton-78 9.2 290
xenon-124 18 570
isotope half-life 1024 years 1030 seconds
tellurium-128 2.2 69

Tellurium-128's half-life is over 160 trillion times greater than the age of the universe (which is 4,35*1017 seconds).[4]

  • List of elements by stability of isotopes
  • List of nuclides
  • Orders of magnitude (time)
  • Lists of isotopes, by element

  1. ^ Reaching the limits of nuclear stability, M. Thoennessen, Rep. Prog. Phys. 67 (2004), pp. 1187–1232, §2.3, doi:10.1088/0034-4885/67/7/R04.
  2. ^ "Periodic Table - Ptable".
  3. ^ 14
    C
    is used in radiocarbon dating.
  4. ^ Walker, John. "Barely Radioactive Elements". www.fourmilab.ch. Retrieved 2018-03-09.

  • Radioactive isotope table "lists ALL radioactive nuclei with a half-life greater than 1000 years", incorporated in the list above.
  • The NUBASE2020 evaluation of nuclear physics properties F.G. Kondev et al 2021 Chinese Phys. C 45 030001. The PDF of this article lists the half-lives of all known radioactives nuclides.

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