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Half-life in (radio)chemistry is the length of time it takes, on average, for a radionuclide (radioactive nuclide) to decay to something else, and leave one-half of its original mass behind. Half-life is logarithmic, so, after a second half-life, one quarter of the mass remains, etc., making a sequence 1/2, 1/4, 1/8, 1/16, etc.
One equation for half-life - there are several - all the same - is ...
AT = A0 2(-T/H)
... where A0 is the starting activity (or mass), AT is the activity after some time T, and H is the half-life in units of T.
One complication is that many radionuclides decay to other radionuclildes, each with their own half-life. As a result, analysis of half-life requires differentiation between different radionuclides, otherwise the results can be in error.
The reason for the last statement is that activity is defined as the number of disintegration's per unit of time, i.e. one curie of activity is defined as the amount of material that exhibits 3.7 x 1010 disintegration's (or decays) per second, and if you simply count disintegration rate, without regard to energy or other criteria, your results will often be in error.
What else can I help you with?
What is the best definition of half-life for a radioactive substance?
It indicates how long it takes for the material to decay.
Half life of the element Sodium?
There are several isotopes of Sodium, each with different half lives. The longest lived, Sodium-22, has a half-life of 2.6027 years.If you are interested in a different isotope, ask the question again and be specific about the isotope in the question.
Which element has the lowest half-life?
Bismuth has recently been found to have a no stable isotope and has a half-life of 4.6 x 10^19 years. Also, the simple hydrogen atom (a single proton), is theorized to decay at a rate of 6.6 x 10^33 years. So far all tests to observe a proton decay have failed.
Does ununoctium combine with any element?
Ununoctium is a synthetic element that is highly unstable and has a very short half-life. Due to its extremely rare occurrence and unstable nature, it is unlikely to form stable compounds with other elements.
What is the malleability of lawrencium?
The malleability of lawrencium is not known.
Does half life of any radioactive element decrease when its used?
The half-life can not be changed by any normal means.
What is the shortest half-life of any known radioactive element?
The shortest half-life of any known radioactive element is that of francium-223, which is approximately 22 minutes.
Element with shortest half life?
Technetium-97 has the shortest half-life of any naturally occurring element, with a half-life of about 4.2 million years. Artificially produced elements typically have even shorter half-lives, with some lasting only fractions of a second.
The rate of decay of a radioactive element is measured by its what?
The rate of decay of a radioactive element is measured by its half-life, which is the time it takes for half of a sample of the element to decay. This measurement is used to determine the stability or instability of the element and to predict its rate of decay over time.
How would the half life equation of aluminum be balanced differently?
Not exactly sure what you mean about "aluminum's half life equation." Exponential decay, from where we get the half-life equation from, has nothing to do with mass, atomic number, etc... and therefore has nothing to do with any particular isotope.
If a radioactive element half life is 500000 years given 20 grams of the element how much is left after 4 half lives?
Just divide the original amount by 2, 4 times: 10; 5; 2.5; 1.25. The final number is the answer.
What can element 117 do?
Element 117 was announced in January 2010, and it has a half life of around 0.078 seconds. It hasn't been studied enough for any of the properties to be determined.
How do you use the word half-life in a sentence?
"The radioactive decay of any atom is associated with the emission of a charged particle (alpha or positive or negative beta) from or the capture of an electron by the nucleus."Nucleonics Fundamentals by David B. Hoisington 1959; page 62.
What is radioactive half life of an element?
The half-life of a radioactive element is the time required for one-half of the nuclei of a radioisotope sample to decay to products.Half-life (t½) is the time required for a quantity to fall to half its value as measured at the beginning of the time period.
What is the best definition of half-life for a radioactive substance?
It indicates how long it takes for the material to decay.
If a 100 g sample of a radioactive element decays to 25 g in 4 days what is the half-life of the element?
If a radioactive sample contains 1.25g of an isotope with a half-life of 4.0 days, then 0.625g (1/2) of the isotope will remain after 4.0 days, 0.3125g (1/4) after 8.0 days, 0.15625g (1/8) after 12.0 days, etc. AT = A0 2(-T/H)
How do you shorten the half-life of a radioactive element?
Making any change in the half-life of an isotope of any element is generally something that lies outside our abilities. A very few radioactive materials have demonstrated a change in their half-lives when bathed in intense magnetic fields. Generally, however, the half-life on a given radionuclide is not something that can be changed. A number of experiments have been conducted wherein investigators have deliberately sought to influence radioactive half-life, but in all but the rarest cases, radionuclides are sublimely resistant to having their half-lives changed.
