Cobalt 5. Also used to irradiate fruit fly larvae in order to contain and eradicate outbreaks, as an alternative to the use of toxic pesticides. Zinc Produced in cyclotrons. Technetiumm 6. Produced in 'generators' from the decay of molybdenum, which is in turn produced in reactors. Caesium Ytterbium Iridium Also used to trace sand to study coastal erosion. Gold 2. Also used to trace factory waste causing ocean pollution, and to study sewage and liquid waste movements.
Americium Radioisotope Half-life Use Phosphorus Yttrium 64 hours Used for liver cancer therapy. Molybdenum Iodine 8. Samarium Lutetium 6. Used to treat a variety of cancers, including neuroendocrine tumours and prostate cancer. Radioisotope Half-life Use Carbon Also used to detect heart problems and diagnose certain types of cancer.
Nitrogen 9. Oxygen 2. Fluorine 1. Used in a variety of research and diagnostic applications, including the labelling of glucose as fluorodeoxyglucose to detect brain tumours via increased glucose metabolism. Copper Gallium Iodine Thallium Used to predict the behaviour of heavy metal components in effluents from mining waste water. Used in gamma radiography, gauging, and commercial medical equipment sterilisation.
Used to study sewage and liquid waste movements. Used as a radiotracer to identify sources of soil erosion and depositing, and also used for thickness gauging.
Used in gamma radiography. Used to trace sand movement in river beds and on ocean floors, and to trace sand to study coastal erosion. Used to image the brain, thyroid, lungs, liver, spleen, kidney, gall bladder, skeleton, blood pool, bone marrow, heart blood pool, salivary and lacrimal glands, and to detect infection.
Currently in clinical trials. Supplied in wire form for use as an internal radiotherapy source for certain cancers, including those of the head and breast. Many people think that the half-life of a radioactive element represents the amount of time an element is radioactive.
In fact, it is the time required for half—not all—of the element to decay radioactively. Occasionally, however, the daughter element is also radioactive, so its radioactivity must also be considered.
The expected working life of an ionization-type smoke detector described in the opening essay is about 10 years. A half-life of y may seem long to us, but it is not very long as half-lives go.
Uranium, the most common isotope of uranium, has a half-life of about 4. On the other hand, some nuclei have extremely short half-lives, presenting challenges to the scientists who study them. The longest-lived isotope of lawrencium , Lr, has a half-life of 3.
As of this writing, the largest atom ever detected has atomic number , mass number , and a half-life of ns. Can you imagine how quickly an experiment must be done to determine the properties of elements that exist for so short a time? Learning Objectives To define half-life. To determine the amount of radioactive substance remaining after a given number of half-lives.
Answer 0. Solution We begin by determining how many half-lives are represented by For example, if an ancient dead tree contains half the expected amount of carbon, it must have died about 5, years ago. Radioactive decay causes a reduction in the number of unstable nuclei in a sample. In turn, this reduces the count rate measured by a detector such as a Geiger-Muller tube.
Another way to define the half-life of a radioactive isotope is the time taken for count rate from a sample to decrease by a half. The table shows how the count rate of an isotope might change over time. Notice how the count rate falls to half its previous value every four days.
This is the half-life of the isotope. Use the table to determine the net decline, expressed as a ratio, after 6 half-lives. Half-life Radioactive decay is a random process.
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