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Radioactive Decay
Also known as nuclear decay, radioactive decay is the decrease of radiation through time.
540 Questions
What does carbon dating have to do with the fossil record?
Nothing. Something must contain carbon to be carbon dated. By definition fossils are mineralized and contain no carbon.
How is the age of an object determined in radio carbon dating?
Carbon-14 breaks down into Carbon-12 at a measurable rate. All the Carbon-14 in an object is fixed once it is finished(or dead) and then it begins to decay. So to determine the age you need to know(or guess) what the ratio of 14 to 12 was to begin with and see how much Carbon-14 is degraded to get the age.
What is the nuclear decay equation for zirconium 97?
Zirconium does not have an isotope with mass 97.
Radon is a radioactive gas that can cause cancer.
How do radioisotopes of an element differ feom other isotopes?
Radioisotopes are "radioactive isotopes"; they are not stable. Radioactive atoms will decay, or break apart into other atoms, by emitting an electron, or a neutron or a positron or an alpha particle (2 protons and two neutrons). The rate at which this happens is measured by the "half-life"; after one half-life, half of the atoms will have decayed. After another half-life, half of the remaining atoms will have decayed.
Atoms with short half-lives are highly radioactive, and can be fairly dangerous. Atoms with long half-lives are only slightly radioactive, and aren't all that dangerous.
What is the product of radioactive decay called?
Product of radioactive decay 42He is an alpha particle
Why does thorium undergo radioactive decay?
The ratio neutrons/protons in radioactive isotopes is the cause of their innstability.
Is there Radioactive decay in microwaves?
No. Radioactive decay is the breakdown of the nucleus of an atom due to its instability. This may emit radiation in the form of gamma rays or subatomic particles.
Microwave "radiation" is the name given to electromagnetic waves in a certain range of frequencies. It differs from gamma rays, x-rays, and visible light only in frequency and energy.
What kind of nuclear decay occurs within most smoke detectors?
Many smoke detectors use Americium-241, which emits alpha rays, to keep air ionized.
How many protons are needed for a element to be naturally radioactive?
Whether an ISOTOPE (not element) is naturally radioactive depends not only on the number of protons, but also on the number of neutrons. For EVERY element, there are radioactive isotopes.There has to be a certain relationship between the number of protons and the number of neutrons, but the relationship isn't a simple one.
Why is igneous rock best for radiometric dating?
What method, and what materials, are best for dating depends on what exactly you are after.
"Carbon dating" is the technique used to calculate how long ago a living organism died.
Here's how it works. Cosmic rays from space hit atoms in the atmosphere, and in some cases will generate thermal neutrons. Nitrogen-14 atoms in the upper atmosphere absorb a few of those neutron, become unstable, and then emit a proton. This changes the Nitrogen-14 (atomic number 7) to carbon-14 (atomic number 6). This process has been going on for a very long time, so there's a relatively constant - but low - percentage of carbon 14 in the atmosphere. Living things breathe in the carbon-14 (along with oxygen and ordinary nitrogen) and the biological processes incorporate this carbon-14.
Carbon-14 is slightly radioactive, and decays with a half-life of 5760 years. As long as you are alive, you keep replenishing your supply of carbon-14. But when you (or any other living thing) dies, it's no longer getting fresh carbon-14, and the existing carbon-14 continues to decay.
By measuring the amount of carbon-14 remaining in any organic material, we can calculate approximately how long ago the organism died. It's fairly accurate back to about 10,000 years, and sort-of accurate back to about 60,000 years. After that, the proportion of carbon-14 that remains is too tiny for accurate analysis.
This only works with living things, and only within the past 60,000 years.
This also assumes that there have been no discontinuities in the formation of carbon-14 in the atmosphere. If there had been a supernova explosion within about 50 light years, a spike in cosmic rays might have caused a spike in carbon-14 production, and carbon-dating analysis might indicate that the sample was younger than it really was.
How does a nuclear reaction take place?
First nuclear reactions always involve the nucleus and except for K capture beta decay never involve any of the electrons around the nucleus.
There are seven different types of ordinary nuclear reactions:
- fission, a massive nucleus splits into two lighter fragment nuclei (about 1/3 & 2/3 the mass of the original nucleus) and several free neutrons, fission can happen spontaneously in some isotopes (e.g. plutonium-240) but is usually triggered by the capture of a neutron, as fission always produces free neutrons it is possible to produce a neutron chain reaction to keep the process going
- fusion, light nuclei join forming a heavier nucleus, this reaction can only happen under conditions of very high temperature and pressure (causing the nuclei to be fully ionized, traveling at high velocity, and pressed tightly together) it is very hard to to get started and keep going (except deep inside stars) Note that fusion is the only one of these seven nuclear reactions that is affected in any way by the temperature or pressure of the environment it happens in
- alpha decay, a nucleus spontaneously ejects a helium nucleus (i.e. alpha particle)
- beta- decay, a neutron in the nucleus spontaneously transforms into a proton and the nucleus ejects an electron and an electron antineutrino
- beta+ decay, a proton in the nucleus spontaneously transforms into a neutron and the nucleus ejects an positron and an electron neutrino
- K capture beta decay, a proton in the nucleus spontaneously transforms into a neutron and the nucleus captures an electron from the innermost (i.e. K) electron shell and ejects an electron neutrino
- gamma decay, a nucleus in a metastable (i.e. excess energy) state spontaneously relaxes its proton and/or neutron shells to a lower energy state and ejects a gamma photon with an energy equal to the energy lost in the nucleus
However if you include other subatomic particles not present in ordinary matter (e.g. muons, antimatter particles, strange particles) a much wider and more confusing variety of nuclear reactions can happen that are beyond the scope of the original question. I will only mention one of these nuclear reactions: muon catalysed cold fusion. This is interesting because it permits the fusion nuclear reaction to happen at ordinary room temperature.
In muon catalyzed cold fusion the electrons around hydrogen nuclei are replaced with muons (particles identical to electrons in every way except that they have 200 times the mass), being much more massive than electrons their orbitals are much smaller. So much smaller that the nuclei can come close enough to each other at ordinary room temperature that the nuclei can fuse! The fusion energy release causes the product nucleus to lose its muons and become ionized. This process is called "muon catalyzed" because these free muons can now replace electrons around fresh hydrogen nuclei, repeating the nuclear reaction over and over without requiring any additional muons. The only problem with muon catalyzed cold fusion is that the muons required to begin this nuclear reaction are very expensive to produce.
Can radium bombs be very destructive as it is million times radioactive than uranium?
The reason why an atomic bomb produces such a large explosion is that certain radioactive isotopes, such as U-235 or plutonium, can be made to undergo a chain reaction in which all the atoms will decay in a very short period of time (a small fraction of a second) releasing all the energy at once. Radium does not do that. However, if you had a substantial quantity of radium you could certainly use it to create radioactive contamination which could induce cancer in many people. That is known as a "dirty bomb".
What radioactive decay processes have no transmutation?
Only gamma, it is the process by which a metastable excited nuclear isomer of an isotope relaxes down to the ground state of the same isotope. Some metastable states must undergo multiple gamma decays through less excited metastable states to reach the ground state.
beta
Could carbon dating be used on stone tablets?
Carbon Dating can only be used on something that contains carbon. Therefore the stone tablet would have to have Carbon it it's structure (Carbonate) , or it would need to be covered in soot or ash.
The lightest "element" that can undergo radioactive decay is the isotope hydrogen-3, which undergoes beta decay. The lightest element with no radioactively stable isotopes is technetium, and its isotopes have different modes of decay.
Why is the level of radon gas in houses different in different parts of the country?
One very definite effect having to do with location is the underlying bedrock. Two houses of identical construction may have very different radon levels if the underlying bedrock in the area is granite vs. limestone.
Radioactive decay is chemical reaction or?
it is type of nuclear reaction because nucleus is involve in this type of reaction while in ordinary chemical reaction only valance electron of atoms involve
What is the scientific calculation of the radiation emitted from various radioactive sources?
I would expect the total radiation to be equal to the sum of the individual radiations.
Why is radioactive decay is good method of measuring the absolute age of ancient fossils?
There are different types of atoms with the same chemical properties but with different numbers of neutrons in the atomic nucleus. These are called "isotopes". The most common element in most living organisms is carbon, which comes in two isotopes; carbon 12, which is normal ordinary carbon and carbon 14, which is very slightly radioactive. The radioactivity means that it will decay, changing into some other element, very slowly.
The proportion of carbon 12 to carbon 14 is pretty steady, so as living things grow, they take in carbon 12 and carbon 14 in their food and air. When the plant or animal dies, they stop taking in new carbon. The carbon 12 remains the same, while the carbon 14 decays into something else very slowly. When we find the remains or the fossil of the dead animal or plant, we can measure how much carbon 12 and how much carbon 14 there is, and calculate how long it has been since the animal died.
