Hydrogen-7 ( about 23x10E-24) has the shortest half life.
You may wonder which naturally-occurring element has the shortest half-life. That would be francium, element 87, whose longest-lived isotope, francium-223, has a half-life of 22 minutes, decaying either into radium by beta decay or astatine by alpha emission.
Bismuth-209 (209Bi) is the isotope of bismuth with the longest known half-life of any radioisotope that undergoes α-decay (alpha decay). It has 83 protons and a magic number of 126 neutrons, and an atomic mass of 208.9803987 amu (atomic mass units).
By exciting or deforming the atom's electrons into states that overlap less with the nucleus, the half-life can be increased.
There is a certain number, called "half-life", that characterizes all nuclei of this type. As an example, suppose the half-life of A is 6 minutes. This means that at any given instant each nucleus of type A has a 50% probability of decaying within the next 6 minutes.
For example: The half-life of Ambien is about 2 hours. So if you take Ambien after 2 hours the plasma concentration will be reduced to half, after 2 more hours the remaining blood levels will be reduced by another half - so a quarter will be left.
When focusing on the main objectives, Half-Life is about 12 Hours in length. If you're a gamer that strives to see all aspects of the game, you are likely to spend around 15½ Hours to obtain 100% completion.
If the half-life is 12 hours, you'll reach a steady state at the beginning of the third day (after 48 hours).
For the most common uranium isotope, U-238, the half-life is 4.5 billion years, about the age of the solar system.
This is why radiocarbon dating is only useful for dating objects up to around 50,000 years old (about 10 half-lives).
If the sample is left to decay for 90 years, this would represent approximately 3 half-lives. We can consider the decay as a timeline of the "life" of the isotope. After each half-life, one-half of the mass will remain. Each arrow in the above timeline represents one half-life decay cycle.
Most living things contain carbon-14, an unstable isotope of carbon that has a half-life of around 5,000 years.
Hydrogen-7 ( about 23x10E-24) has the shortest half life.
So light is the fastest thing. Nothing can go faster than that. It's kind of like the speed limit of the universe.
Uranium-238 has a half-life of 4.5 billion years.
Iodine, strontium and caesium were the most dangerous of the elements released, and have half-lives of 8 days, 29 years, and 30 years respectively. The isotopes Strontium-90 and Caesium-137 are therefore still present in the area to this day.
Their half-life is 30 years. That is, half of these radionuclides have already ceased to be dangerous. In the next 30 years, another half of the remaining volume will decay, and so on.
Uranium is also a toxic chemical, meaning that ingestion of uranium can cause kidney damage from its chemical properties much sooner than its radioactive properties would cause cancers of the bone or liver.
The half-life of a drug is the time it takes for the amount of a drug's active substance in your body to reduce by half. This depends on how the body processes and gets rid of the drug. It can vary from a few hours to a few days, or sometimes weeks.
Even further, 94 to 97% of a drug will have been eliminated after 4 to 5 half-lives. Thus, it follows that after 4 to 5 half-lives, the plasma concentrations of a given drug will be below a clinically relevant concentration and thus will be considered eliminated.
Half-life can determine risk.
Half-life is crucial when determining the danger of an isotope. If a radioactive substance has a very long half-life, we know that it will remain radioactive for a very long time. The longer a substance remains radioactive, the more dangerous it is.
Half-Life is a 1998 first-person shooter (FPS) game developed by Valve and published by Sierra Studios for Windows. It was Valve's debut product and the first game in the Half-Life series.
The time it takes for 14C to radioactively decay is described by its half-life. C has a half-life of 5,730 years. In other words, after 5,730 years, only half of the original amount of 14C remains in a sample of organic material. After an additional 5,730 years–or 11,460 years total–only a quarter of the 14C remains.
Founders Gabe Newell and Mike Harrington had 20 years at Microsoft between them and plenty of money for a hefty safety net when they ventured out on their own in 1996. It took two years to get Half-Life on shelves.