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Topic: Unstable isotope

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	The Structure of the Physical Universe, Chapter XXXI
		In natural beta radioactivity a single beta emission is normally sufficient as the unstable isotopes are seldom very far outside the zone of beta stability and alpha stability is not involved.
		The unstable isotopes which are responsible for natural radioactivity in the local environment originate in two ways: by past or present inflow of matter from regions where the magnetic ionization level is zero, and by atomic transformations initiated by high energy particles such as those in the cosmic rays.
		In such reactions stable isotopes of one kind or another are converted into related unstable isotopes and the latter then become sources of radioactivity, mostly of the beta type.
	www.reciprocalsystem.com /spu/spu31.htm (4203 words)

	Analytica
		The quantitative relationship of isotopes (calculated by the number of atoms) is measured between pairs of isotopes for a given element.
		Isotope dilution is a sophisticated method for quantitative analysis of elements.
		After "spiking" the sample with a stable enriched isotope of an element, the original concentration of that element can be calculated from the measured change in one or more isotope ratios.
	www.analytica.se /hem2001/eng/analyse/industri/ovriga_isotop.asp (309 words)

	Name ___________________________________
		Radioactivity - the release of energy(and particles) from an unstable nucleus as it decays.
		Naturalradioactivity is the spontaneous decay of a nucleus (the nucleus emits aradioactive particle).
		Artificialradioactivity is the man-made decay of a nucleus for the purpose of energyproduction.
	midwoodscience.org /stack/regentsreview/14nuclear.htm (776 words)

	The Environmental Literacy Council - Isotopes
		Isotopes differ in their atomic mass, which is the mass of the protons plus the mass of the neutrons, but not in their atomic number, which is determined by the number of an atom's protons.
		Isotopes can be separated to yield higher concentrations of a particular isotope, using techniques such as centrifugal separation and gaseous diffusion that exploit the differences in mass between isotopes.
		Some isotopes have very specific uses, for example the isotope of uranium that has atomic mass 235 is used as a fuel in nuclear reactors; "heavy" water or deuterium, which is formed from hydrogen isotopes that have the atomic mass 2, is used as a moderator in nuclear reactors to slow down the reaction.
	www.enviroliteracy.org /article.php/1255.php (734 words)

	AppendA
		Importantly, the rate at which an unstable 'parent' isotope decays to its 'daughter' isotope is a fixed physical property of the parent isotope, and is known as its half–life.
		The daughter isotope may be stable or unstable, in the latter case decomposing further.
		In other words, the isotope decay process is like a clock which started when the organism died or the rock cooled, where the clock's time can be read by careful measurement of isotope concentrations.
	faculty.uca.edu /~paulh/evorel/appenda.htm (1416 words)

	Evolution and the Fossil Record by John Pojeta, Jr. and Dale A. Springer
		An unstable radioactive isotope, which is the 'parent' of one chemical element, naturally decays to form a stable nonradioactive isotope, or 'daughter,' of another element by emitting particles such as protons from the nucleus.
		The half-life of a radioactive isotope is the length of time it takes for exactly one-half of the parent atoms to decay to daughter atoms.
		Precise laboratory measurements of the number of remaining atoms of the parent and the number of atoms of the daughter result in a ratio that is used to compute the age of a fossil or rock in years.
	www.agiweb.org /news/evolution/datingfossilrecord.html (804 words)

	methods
		Isotopes of a given element have nuclei with the same number of protons but different numbers of neutrons.
		Some isotopes are stable, however radioisotopes are unstable and disintegrate, with the emission of three main types of radiation.
		Tritium (3-H) is an unstable isotope of hydrogen, consisting of a proton, an electron, and two neutrons.
	www.ruf.rice.edu /~bioslabs/methods/radioisotopes/rad1.html (1904 words)

	geotime
		Most isotopes are stable: they have a certain number of protons and a certain number of neutrons that allows the isotope to remain stable forever.
		We measure the amount of parent isotope, the amount of daughter isotope (using a mass spectrometer), and, knowing the rate of decay, we can calculate how many years old a mineral is. Below is a table showing some of the commonly used isotopes for absolute age dating.
		Note that geologists only use isotopes that meet some strict criteria, such as: both parent and daughter isotope must be unique, and not a type we might find commonly occurring in a rock.
	www-class.unl.edu /geol101i/08_geotime.html (2822 words)

	USGS Info Handout: Stable Isotopes and Mineral Resource Investigations in the United States
		Isotopic ratios are measured in the laboratory on an instrument known as a mass spectrometer.
		Likewise, the range of sulfur isotope compositions of the pyrite is intermediate between that expected for leaching of sulfide solely from the underlying volcanic rocks and that expected for sulfide produced from the reduction of seawater sulfate.
		The sulfur isotope compositions of the pyrite and enargite are identical to that expected for sulfur in terrestrial geothermal systems, either derived from leaching of sulfide from igneous rocks or derived as subvolcanic emanations.
	pubs.usgs.gov /info/seal2 (1734 words)

	Glossary
		Deuterium: "Heavy hydrogen", a stable isotope having one proton and one neutron in the nucleus.
		Half-life:The period required for half of the atoms of a particular radioactive isotope to decay and become an isotope of another element.
		Isotope: An atomic form of an element having a particular number of neutrons.
	www.world-nuclear.org /info/inf51.html (2742 words)

	[No title] (Site not responding. Last check: )
		Isotopes are atoms of the same element containing the same number of protons but with varying numbers of neutrons in their nucleus.
		Radioactive decay is the spontaneous transformation of an unstable isotope of one element into the atom of another isotope.
		Second, any assumptions regarding initial conditions, such as quantities of parent isotopes or daughter elements originally present in the rock or mineral, can be confirmed or adjusted based on the calculated results of the method.
	cse.cosm.sc.edu /hses/AbsolDat/pages/radio.htm (435 words)

	Absolute Geologic Time (Site not responding. Last check: )
		Rutherford and Soddy (1902) discovered that the rate of decay of a radioactive isotope depends on the amount of the parent isotope remaining.
		Some examples: the half-life for the decay of potassium 40 atoms into argon 40 atoms is about 1.3 billion years, the half-life for the decay of uranium 238 into lead 206 is about 4.5 billion years, and the half-life for the decay of carbon 14 into Nitrogen 14 is 5730 years.
		One half-life after a radioactive isotope is incorporated into a rock there will be only half of the original radioactive parent atoms remaining and an equal number of daughter atoms will have been produced.
	www.columbia.edu /~vjd1/radiometric_dating.htm (498 words)

	Isotope - the comic book lounge
		Those overworked Isotope mail carriers of all varieties have been showing up with armloads of packages from across the globe for the past few days, and as much as we feel sorry for them for the extra work we're putting them through...
		From 11am until 9pm the Isotope will be open and available for anyone making those last-minute submissions, and from there we will continue taking submissions until the witching hour at Jade Bar mere blocks down the street.
		The Isotope is proud to announce that for the upcoming weeks we will be bringing our guerrilla cinema to you each Wednesday, beaming a weekly dose of hand picked cult pictures to your home, office, lap or desktop.
	www.isotopecomics.com /archive/2006_03_01_index.html (3186 words)

	Fundamentals (Site not responding. Last check: )
		For example, the two lightest isotopes of hydrogen are stable, while the third is unstable or radioactive.
		Unstable isotopes decay until the decay product is stable.
		The half-life for a particular isotope is a constant and cannot be increased or decreased by any chemical or physical means.
	www.runet.edu /~fac-man/Safety/Radiation/chp4.htm (2939 words)

	Chemistry 1020--Spring 2000--Lecture 8 Notes
		Isotopes with much shorter half lives must have been formed either artificially by a transmutation reaction, or by some process which produces the isotope.
		Putting isotopes in the ground water can be an effective means to trace the flow of ground water.
		Using isotopically labeled compounds as intermediates in cellular pathways has been a very important technique in determining the intermediates by which one compound is converted to another in cells.
	www.chem.fsu.edu /editors/rlight/1020s00/lecture8.htm (1631 words)

	How it Works
		The unstable isotope, C-14, is created by the breakdown of nitrogen in our atmosphere when it is struck by cosmic radiation.
		This unstable isotope travels to earth by atmospheric activity, such as storms, and becomes fastened in the biosphere.
		The unstable C-14, however, is continually being replenished as long as the animal (or plant) continues to live and eat.
	www.upei.ca /~phys221/mpmacphee/How_it_Works/how_it_works.html (417 words)

	Geologic time
		Isotope: a form of an element which has the same number of protons and electrons in it, but a different number of neutrons.
		Isotopes are either stable (they do not spontaneously decay) or unstable (they will spontaneously decay by some type of nuclear decay process).
		This constant decay is known as the half-life of the isotope.
	www.ux1.eiu.edu /~cfjps/1300/time.html (1528 words)

	Cents of Time , Educational Resources for K-16
		When the number of unstable neutrons and protons changes to a stable number, the new isotope is termed a daughter isotope.
		All of the isotopes in the penny element when it is formed are parent elements, which are heads for this activity.
		This means all of the isotopes in the penny element have been converted to stable daughter isotopes.
	www.uky.edu /KGS/education/cents_time.htm (1868 words)

	HSC Online
		Isotopes of an element are atoms of that element containing the same number of protons but different numbers of neutrons.
		In a stable isotope nucleus, the protons and neutrons are in a low energy level and are unable to emit radioactivity.
		The time for the radioactivity level from a given amount of radioactive isotope to be halved is called its half-life.
	hsc.csu.edu.au /chemistry/core/identification/chem925/925net.html (1236 words)

	ORNL Review Vol. 34, No. 2, 2001
		Many radioactive isotopes are quite useful in the diagnosis or treatment of diseases, biological and environmental studies, archeology, national security, and energy generation.
		Each unstable isotope is characterized by its half-life—the time it takes for half of the sample to decay.
		Short-lived isotopes cannot be found naturally on the earth because they have long since decayed in that our planet was formed about 4 billion years ago.
	www.ornl.gov /info/ornlreview/v34_2_01/search.htm (2836 words)

	Radioactivity
		Sometime after it is created an unstable nucleus will spontaneously emit radiation which takes it to a lower energy state that may or may not be stable.
		It follows that when a large sample of unstable nuclei are present, the number that decay during any one short time interval is proportional to the number of nuclei present at the beginning of that interval.
		The isotope of mass 137 is radioactive with a half-life of 30.25 years.
	www4.ncsu.edu /~mowat/H&M_WebSite/Radioactivity/Radioactivity.html (1642 words)

	[No title]
		Positive alpha particles (4He) and positrons (+1e)are attracted to the negative side of the field, Negative beta particles (-1e) are attracted to the positive side and gamma rays which are uncharged pass right between the positive and negative sides of the field without being deflected.
		Natural vs. Artificial Radioactivity The stability of an isotope is based on the ratio of neutrons to protons in its nucleus.
		The isotope may not be harmful to the body and must have a short half life so it is quickly eliminated from the body.
	midwoodscience.org /stack/regentsreview/nuclear.doc (978 words)

	DETERMINING AGE OF ROCKS AND FOSSILS
		In general, with the exception of the single proton that constitutes the nucleus of the most abundant isotope of hydrogen, the number of neutrons must at least equal the number of protons in an atomic nucleus, because electrostatic repulsion prohibits denser packing of protons.
		Many elements have some isotopes that are unstable, essentially because they have too many neutrons to be balanced by the number of protons in the nucleus.
		The teacher should have each team report how many pieces of parent isotope remain, and the first row of the decay table (Figure 2) should be filled in and the average number calculated.
	www.ucmp.berkeley.edu /fosrec/McKinney.html (2494 words)

	Quantum Tech Water Fact Sheet
		A metal is a stable isotope and thus proves toxic to the human body.
		Also, the isotopes actually used by biological entities are very specific; of the 35 needed elements, only one unstable isotope from each of these atomic elements is actually utilized with six exceptions: hydrogen, oxygen, magnesium, calcium, tin and gold (see table below).
		An isotope is a variant of any element distinguished by having a different neutral charge neutron particle count in the atoms nucleus.
	www.life-enthusiast.com /ormus/qt_fact_sheet.htm (1324 words)

	The Water (Site not responding. Last check: )
		The answer is that they are attempting to convert incorrect isotopes to useable isotope frequencies with a resultant expenditure of energy and subsequent stress placed on the various biological systems.
		Also, the isotopes actually used by biological entities are very specific – of the 34 needed elements, only one unstable isotope from each of these atomic elements is actually utilized with five exceptions – hydrogen, oxygen, magnesium, tin and gold (see table below).
		The quantum property of isotopes, which is of particular importance to the “Frequency of Life” water, is the frequency or oscillation rate.
	www.life-enthusiast.com /tamahi/water.htm (964 words)

	Half Life
		The isotopic distribution of carbon on the earth is roughly 99% carbon 12 (with 6 protons and 6 neutrons) and 1% carbon 13 (with 6 protons and 7 neutrons).
		This rare, unstable isotope is produced in the upper atmosphere from ordinary nitrogen 14.
		Potassium-argon dating is used to determine the age of igneous rocks based on the ratio of an unstable isotope of potassium to that of argon.
	hypertextbook.com /physics/modern/half-life/index.shtml (1950 words)

	Cochise College (Site not responding. Last check: )
		-occurs when a neutron inside of an unstable isotope decays into a proton, neutrino, and electron; the proton stays within the nucleus, while the electron and neutrino are ejected at great speeds.
		The loss of a beta particle increases the atomic number by one and the loss of an alpha particle decreases the atomic number by 2 and the atomic mass number by 4.
		By determining the ratio of the parent isotopes to their daughter products, the age of the sample can be determined.
	skywalker.cochise.edu /wellerr/GLGP-08.htm (627 words)

	Radioactivity and Nuclear Reactions (Site not responding. Last check: )
		Isotopes are forms of the same element that have different numbers of neutrons.
		The reason is that dangerous radioactive isotopes left on the island by the expolsion have not decayed into safe, stable isotopes.
		The reason radioactive isotope are so valuable in the treatment of illnesses and why patients don't mind using them is that if the technetium or the isotopes does its job, surgery may not be required.
	www.uh.edu /hti/cu/1999/v02/04.htm (4928 words)

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