LIST OF THE HALF-LIVES OF COMMONLY ENCOUNTERED RADIONUCLIDES

Element	Isotopes w/ Half life
Actinium	Ac-225 - 10.0 days Ac-227 - 21.773 years Ac-228 - 6.13 hours
Americium	Am-241 - 432.2 years Am-242 - 16.02 hours Am-242m - 152 years Am-243 - 7380 years
Antimony	Sb-124 - 60.20 days Sb-125 - 2.77 years Sb-126 - 12.4 days Sb-126m - 19.0 minutes Sb-127 - 3.85 days
Argon	Ar-41 - 1.827 hours
Astatine	At-217 - 0.0323 seconds At-218 - 2 seconds
Barium	Ba-137m - 2.552 minutes Ba-139 - 82.7 minutes Ba-140 - 12.74 days Ba-141 - 18.27 minutes Ba-142 - 10.6 minutes
Beryllium	Be-10 - 1.6E6 years Be-7 - 53.44 days
Bismuth	Bi-210 - 5.012 days Bi-211 - 2.14 minutes Bi-212 - 60.55 minutes Bi-213 - 45.65 minutes Bi-214 - 19.9 minutes
Bromine	Br-82 - 35.30 hours Br-83 - 2.39 hours Br-84 - 31.80 minutes
Cadmium	Cd-113m - 13.6 years Cd-115m - 44.6 days
Calcium	Ca-41 - 1.3E5 years Ca-47 - 4.53 days
Californium	Cf-252 - 2.638 years
Carbon	C-11 - 20.38 minutes C-14 - 5730 years
Cerium	Ce-141 - 32.50 days Ce-143 - 33.0 hours Ce-144 - 284.3 days
Cesium	Cs-134 - 2.062 years Cs-134m - 2.90 hours Cs-135 - 2.3E6 years Cs-136 - 13.1 days Cs-137 - 30.0 years Cs-138 - 32.2 minutes
Chromium	Cr-51 - 27.704 days
Cobalt	Co-56 - 78.76 days Co-57 - 270.9 days Co-58 - 70.8 days Co-60 - 5.27 years
Copper	Cu-61 - 3.408 hours Cu-64 - 12.701 hours
Curium	Cm-242 - 162.8 days Cm-243 - 28.5 years Cm-244 - 18.11 years Cm-245 - 8500 years Cm-246 - 4730 years Cm-247 - 1.56E7 years Cm-248 - 3.39E5 years
Europium	Eu-152 - 13.33 years Eu-154 - 8.8 years Eu-155 - 4.96 years Eu-156 - 15.19 days
Fluorine	F-18 - 109.74 minutes
Francium	Fr-221 - 4.8 minutes Fr-223 - 21.8 minutes
Gadolinium	Gd-152 - 1.08E14 years
Gallium	Ga-67 - 3.261 days
Gold	Au-198 - 2.696 days
Holmium	Ho-166m - 1.20E3 years
Hydrogen	H-3 - 12.35 years
Indium	In-111 - 2.83 days In-113 - 1.658 hours In-115 - 5.1E15 years
Iodine	I-123 - 13.2 hours I-125 - 60.14 days I-129 - 1.57E7 years I-130 - 12.36 hours I-131 - 8.04 days I-132 - 2.30 hours I-133 - 20.8 hours I-134 - 52.6 minutes I-135 - 6.61 hours
Iridium	Ir-192 - 74.02 days
Iron	Fe-55 - 2.7 years Fe-59 - 44.53 days
Krypton	Kr-83m - 1.83 hours Kr-85 - 10.72 years Kr-85m - 4.48 hours Kr-87 - 76.3 minutes Kr-88 - 2.84 minutes
Lanthanum	La-140 - 40.272 hours La-141 - 3.93 hours La-142 - 92.5 minutes
Lead	Pb-209 - 3.253 hours Pb-210 - 22.3 years Pb-211 - 36.1 minutes Pb-212 - 10.64 hours Pb-214 - 26.8 minutes Pb-214 - 26.8 minutes
Manganese	Mn-52 - 5.591 days Mn-52m - 21.1 minutes Mn-54 - 312.5 days Mn-56 - 2.579 hours Mn-57 - 36.08 hours
Mercury	Hg-197 - 64.1 hours Hg-203 - 46.60 days
Molybdenum	Mo-93 - 3.5E3 years Mo-99 - 66.0 hours
Neodymium	Nd-147 - 10.98 days
Neptunium	Np-237 - 2.14E6 years Np-238 - 2.117 days Np-239 - 2.355 days Np-240 - 65 minutes Np-240m - 7.4 minutes
Nickel	Ni-59 - 7.5E4 years Ni-63 - 96 years Ni-65 - 2.520 hours
Niobium	Nb-93m - 13.6 years Nb-95 - 35.15 days Nb-95m - 86.6 hours Nb-97 - 72.1 minutes Nb-97m - 60 seconds
Nitrogen	N-13 - 9.97 minutes N-16 - 7.13 seconds
Oxygen	O-15 - 122.24 seconds
Palladium	Pd-107 - 6.5E6 years Pd-109 0- 13.427 hours
Phosphorus	P-32 - 14.29 days
Plutonium	Pu-238 - 87.74 years Pu-239 - 24065 years Pu-240 - 6537 years Pu-241 - 14.4 years Pu-242 - 3.76E5 years Pu-243 - 4.956 hours Pu-244 - 8.26E7 years
Polonium	Po-210 - 138.38 days Po-211 - 0.516 seconds Po-212 - 0.305 microseconds Po-213 - 4.2 microseconds Po-214 - 164.3 microseconds Po-215 - 0.00178 seconds Po-216 - 0.15 seconds Po-218 - 3.05 minutes
Potassium	K-40 - 1.27E9 years K-42 - 12.36 hours K-43 - 22.6 hours
Praseodymium	Pr-143 - 13.56 days Pr-144 - 17.28 minutes Pr-144m - 7.2 minutes
Promethium	Pm-147 - 2.6234 years Pm-148 - 5.37 days Pm-148 - 41.3 days Pm-149 - 53.08 hours Pm-151 - 28.40 hours
Protactinium	Pa-231 - 3.28E4 years Pa-233 - 27.0 days Pa-234 - 6.70 hours Pa-234m - 1.17 minutes
Radium	Ra-223 - 11.434 days Ra-224 - 3.66 days Ra-225 - 14.8 days Ra-226 - 1600 years Ra-228 - 5.75 years
Radon	Rn-219 - 3.96 seconds Rn-220 - 55.6 seconds Rn-222 - 3.824 days
Rhenium	Re-187 - 5E10 years
Rhodium	Rh-103m - 56.12 minutes Rh-105 - 35.36 hours Rh-106 - 29.9 seconds
Rubidium	Rb-86 - 18.66 days Rb-87 - 4.7E10 years Rb-88 - 17.8 minutes Rb-89 - 15.2 minutes
Ruthenium	Ru-103 - 39.28 days Ru-105 - 4.44 hours Ru-106 - 368.2 days Ru-97 - 2.9 days
Samarium	Sm-147 - 1.06E11 years Sm-151 - 90 years Sm-153 - 46.7 hours
Scandium	Sc-44 - 3.927 hours Sc-46 - 83.83 days Sc-47 - 3.351 days Sc-48 - 43.7 hours
Selenium	Se-75 - 119.78 days Se-79 - 65000 years
Silver	Ag-110 - 24.6 seconds Ag-110m - 249.9 days Ag-111 - 7.45 days
Sodium	Na-22 - 2.602 years Na-24 - 15.00 hours
Strontium	Sr-85 - 64.84 days Sr-87m - 2.81 hours Sr-89 - 50.5 days Sr-90 - 29.12 years Sr-91 - 9.5 hours Sr-92 - 2.71 hours
Sulfur	S-35 - 87.44 days
Technetium	Tc-101 - 14.2 minutes Tc-99 - 2.13E5 years Tc-99m - 6.02 hours
Tellurium	Te-125m - 58 days Te-127 - 9.35 hours Te-127m - 109 days Te-129 - 69.6 minutes Te-129m - 33.6 days Te-131 - 25.0 minutes Te-131m - 30 hours Te-132 - 78.2 hours Te-133 - 12.45 minutes Te-133m - 55.4 minutes Te-134 - 41.8 minutes
Terbium	Tb-160 - 72.3 days
Thallium	Tl-201 - 73.06 hours Tl-207 - 4.77 minutes Tl-208 - 3.07 minutes Tl-209 - 2.20 minutes
Thorium	Th-227 - 18.718 days Th-228 - 1.913 years Th-229 - 7340 years Th-230 - 7.7E4 years Th-231 - 25.52 hours Th-232 - 1.41E10 years Th-234 - 24.10 days
Tin	Sn-119m - 293.1 days Sn-123 - 129.2 days Sn-125 - 9.64 days Sn-126 - 1.0E5 years
Tungsten	W-181 - 121.2 days W-185 - 75.1 days W-187 - 23.9 hours
Uranium	U-232 - 72 years U-233 - 1.59E5 years U-234 - 2.445E5 years U-235 - 7.03E8 years U-236 - 2.34E7 years U-237 - 6.75 days U-238 - 4.47E9 years U-240 - 14.1 hours
Vanadium	V-48 - 16.238 days
Xenon	Xe-131m - 11.9 days Xe-133 - 5.245 days Xe-133m - 2.188 days Xe-135 - 9.09 hours Xe-135m - 15.29 minutes Xe-138 - 14.17 minutes
Ytterbium	Yb-169 - 32.01 days
Yttrium	Y-90 - 64.0 hours Y-91 - 58.51 days Y-91m - 49.71 minutes Y-92 - 3.54 hours Y-93 - 10.1 hours
Zinc	Zn-65 - 243.9 days Zn-69 - 57 minutes
Zirconium	Zr-93 - 1.53E6 years Zr-95 - 63.98 days Zr-97 - 16.90 hours

WHY DO WE NEED TO STUDY HALF-LIFE?

WHY DO WE NEED TO STUDY HALF-LIFE?

Since we are dealing with those radioactive elements, and we’d already known that they are emitting energy in the form of radiation spontaneously, the question is: What is happening to the element itself?

All what’s happening to the radioactive elements could be represented (Note: in a simple manner) by putting fuel to your sports car. You drove the car for many hours and many miles were traveled, and sooner or later, you’ll use up all the fuel because it is the source of energy for your engine-powered car.

Fuel= radioactive elements

Energy used by car= the spontaneous radiation of elements

BUT…

THE PROCESS IS NOT LIKE THE EXAMPLE. RADIOACTIVE ELEMENTS GOES IN THE PROCESS OF HALF-LIFE DECAY or EXPONENTIAL DECAY.

So why do we need to study it?

Of course, all radioactive elements are radioactive because they are unstable. To be in a stable state, they need to emit radiation and as they “emit radiation” or “decay”, we cannot predict when the element will decay. However, it is possible to predict what fraction of the nuclei in a sample will decay within any given time.

HALF-LIFE-in the definition given- of a radioactive element is the time that it takes for one half of the atoms of that substance to disintegrate into another nuclear form.

WHAT IS HALF-LFE? (A SIMPLE DEFINITION)

WHAT IS HALF-LIFE?

The half-life of a radioactive element is the time that it takes for one half of the atoms of that substance to disintegrate into another nuclear form.