One of the radioactive substances with the longest half-life is thorium-232, with a half-life of about 14 billion years. Another example is uranium-238, which has a half-life of about 4.5 billion years.
Terminal half-life is the time it takes for the concentration of a drug in the body to decrease by half during the elimination phase, after reaching steady state. It is used to estimate how long a drug will stay in the body once the dosing is stopped. Terminal half-life is influenced by factors such as drug metabolism and elimination rate.
The order of half-life from shortest to longest is: P32 (phosphorus-32), S35 (sulfur-35), C14 (carbon-14), and H3 (tritium).
For elements with no stable isotopes, the mass number of the isotope with the longest half-life is in parentheses.
For elements with no stable isotopes, the mass number of the isotope with the longest half-life is in parentheses.
Uranium has the longest half-life element
Plasma decay refers to the time that it takes for the concentration in blood plasma of a substance to reach one-half of its steady-state value. This is also referred to as the plasma half-life.
One of the radioactive substances with the longest half-life is thorium-232, with a half-life of about 14 billion years. Another example is uranium-238, which has a half-life of about 4.5 billion years.
half life
Plasma half life is the most important factor determining the dosage frequency. it also decides the time taken for the drug to reach steady state plasma concentration, which takes about 4-5 half lives to achieve. we can calculate how long the drug is going to stay in the body by knowing its half life as it is the time taken for the drug concentration to halve.
I believe it is selenium 82 with a half life of 1.3*10 to the 20 years or 130 quintillion years!
Phosphorus, iron, and iodine all have at least one isotope that is stable, and any of these would do for the longest half life. In fact, the radioactive isotopes of phosphorus are all synthetic, so radioactive phosphorus is not found in nature.
The longest-lived isotope currently known is 289Fl with a half-life of ~2.6 s, although there is evidence for a nuclear isomer, 289bFl, with a half-life of ~66 s, that would be one of the longest-lived nuclei in the super-heavy element region.
Tungsten 184 has a half life of nearly 9 sextillion years - which is several trillion times the age of the universe.
The half-life of most hormones ranges from minutes to hours, depending on the specific hormone and its mode of regulation and clearance in the body.
Ununquadium is still being explored. There are 5 confirmed isotopes, and what looks looks two isomers. The longest half-life appears to be 114289Uuq at 2.6 seconds, and the longest isomer appears to be 114289mUuq at 1.2 minutes.
It's terminal elimination half-life after intravenous administration is normally 2 to 4 hours. In some studies involving longer periods of plasma sampling, a longer terminal half-life of about 15 hours was reported.