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A free-moving neutron is absorbed by the nucleus of an atom. This can cause?
Wiki User
∙ 7y ago
Verified answer
the atom to become unstable and rip apart
Wiki User
∙ 7y ago
Describe a characteristic of a fissionable substance that is essential for a chain-reaction to sustain itself?
The fission process is sustained by neutrons. A neutron entering a nucleus and causing fission must be replaced in order to cause the next fission, and so on. So the fissionable substance must emit more neutrons when fission occurs, and enough of them so that despite some being absorbed by the moderator and some leaking from the reactor boundary, there is still enough to maintain the chain reaction. Uranium 235 emits on average about 2.5 neutrons per fission (you might say what is half a neutron, but this is explained by the fact that fissions have a range of possible results, with different numbers of neutrons emitted, and the average is 2.5).
What cause the atom's nucleus to become unstable?
Inside the nucleus of an atom, there is a competition between two principle forces: strong nuclear forces which keep the nucleus together, and electrostatic forces between the protons which want to blow it apart. Different proton-neutron structures causes changes between these two forces which affects the stability of the atom. The exact instant an atom decays is a quantum perturbation. Every time the atom vibrates, it has a chance of overcoming the activation energy barrier for decay.
Is it possible for a chemical to be absorbed through your skin and travel through your bloodstream to cause damage somewhere else in your body?
Yes
Why is plutonium most hazardous when inhaled in particulate form?
Inhaled fine powders are absorbed in lungs and are the cause of lung cancers.
Which principal energy level change by the electron of a hydrogen atom will cause the greatest amount of energy to be absorbed?
n=2 to n=5 , hope that helps
Why fission cannot take place with fast neutron?
In order to cause an atomic nucleus to become unstable so that it will undergo fission, you have to add a neutron. If a slow neutron collides with an atomic nucleus, it will be absorbed into the nucleus and become part of it. The nuclear attraction of the nucleus is strong enough to grab a slow neutron. But a fast neutron cannot be captured because it has too much kinetic energy. The attraction of the nucleus is not enough to stop the motion of a fast neutron. Even if a fast neutron makes a direct hit on an atomic nucleus, it is just going to bounce off.
Why is it eaier to fission uranium 235 with neutrons than alpha particles?
A neutron is smaller and has no charge, so it is able to penetrate to the nucleus far better than an alpha particle (which is larger in size, and has a charge that is repelled by the nucleus). So the neutron is more able to cause critical instability and fission the nucleus.
What aspects of the composition of a nucleus can cause it to be unstable?
The two aspects that cause the nucleus of any element atom to be unstable are:not have the specific neutron/proton ratio to be a stable nucleus, and orhaving number of protons that exceeds the stability limit (exceeding 83).Referring to question below for more information.
What are examples of nuclear changes in mass?
Changes in nuclear mass can happen when, say, radioactive decay occurs and a nucleus loses mass. When an unstable atomic nucleus "adjusts" to a new state, it dumps a particle or particles, and energy, and its mass decreases. Certainly nuclear fission will cause a dramatic reduction in nuclear mass, but this is the actual "breaking up" of a nucleus into smaller nuclei called fission fragments. Perhaps an example will help. The element radon is an inert gas, but it has no stable isotopes. It's most stable isotope, 222Rn, appears as a decay product of radium; it's a radioactive daughter. It turns out that 222Rn decays by alpha emission, and that means that two neutrons and two protons are kicked out of the nucleus. This will produce the radioactive daughter product polonium-218. It is possible for a nucleus to absorb a particle and gain mass. Frequently this will cause nuclear instability (if it doesn't actually initiate fission) and create a radionuclide, which is unstable and will eventually decay. But something like, say, neutron absorption (neutron capture) will result in an atomic nuclei with a greater mass than the original atomic nucleus that absorbed that neutron. It is of note that fusion knits smaller nuclei or particles together to create a larger nucleus, but this may not necessarily be considered a "simple increase" of mass in a nucleus, though the resultant nucleus will be heavier than any constituent nucuei or particles. You may want an example. If we stick some uranium-238 into an operating nuclear reactor, the 238U will absorb a neutron to become 239U, which is heavier by one neutron that the atomic nucleus that absorbed that neutron. (The 239U is unstable and decays in a couple of steps to make 239Pu, which is used as the fissile material in most nuclear bombs and as a fuel in some nuclear reactors.) Use the links below to related articles posted by our friends at Wikipedia, where knowledge is free.
What happens when a neutron hits a large uranium nucleus?
One thing that can happen when a neutron interacts with a uranium atom is called scattering. The neutron "bounces off" the uranium. Aside from scattering, a neutron has a possibility of being absorbed by the uranium nucleus, and this can cause several different reactions, depending on which isotope of uranium is involved in the reaction. It is neutron absorption that is the mechanism utilized in the chain reactions in nuclear weapons and in nuclear reactors. Nuclear fuel, which is often uranium-235, fissions by absorbing a neutron. In the case of uranium-238, we make plutonium by getting that isotope to absorb a neutron. There is a lot more to learn, and you'll find related links below to get you going.
For a fission reaction to fail to be maintained as a chain reaction each fission must produce less than additional fission reaction(s).?
In a continuous chain reaction at a steady rate, which gives a steady power output from a fission reactor, every fission gives rise to another fission. This happens because in every fission 2 or 3 neutrons are produced, some are absorbed or lost, but if just one is captured by another fissionable nucleus, the chain reaction will continue. Apex answer = 1
How does positron emission cause nuclear transmutation?
It is in beta plus decay that we see the positron emitted from the nucleus. (An electron is emitted in beta minus decay.) Within the nucleus of an unstable atom, a proton transforms into a neutron, and a positron is ejected from the nucleus (along with a neutrino). As the nucleus now has one more proton than it did before, its atomic number just went up by one; it is another element.
What is neutron capture?
In short, neutron capture is a nuclear reaction wherein an atomic nucleus captures one (or perhaps more) neutrons. The nucleus is then one nucleon heavier (or perhaps more, if more neutrons are absorbed). The new nucleus may be subject to further transformations, depending on what was formed in the capture process. Many different atomic nuclei can capture a neutron under the right conditions. We often think of uranium or plutonium (nuclear fuels) as atoms that undergo neutron capture. It is, after all, neutron capture that destabilizes the nucleus and can cause nuclear fission. This is the process that we set up when we build a nuclear reactor or a nuclear weapon. We can expose any number of different materials to the neutron flux in operating nuclear reactor. Atoms in the material will undergo neutron capture, depending on the conditions in the ractor, and (primarily) what the material is. In the case of cobalt, we will lower a measured amount of the metal in a suitable form into the reactor via a port. After a desired amount of time, the slug of cobalt, which was cobalt-59, is withdrawn. We now have a slug that has a fair percentage of cobalt-60 in it, and cobalt-60 is radioactive. The isotope emits gamma rays, and the slug is put in a casket of shielding material and can be transported for industrial use. (It might be used to X-ray welds in piping at a remote location, or sterilize band aids or other medical items at the end of a manufacturing process.)
Is neutron a planet in your solar system?
do you know what a neutron planet is if you do could you tell me cause i don't bye
Why has a nucleus?
cause
What composes a neutron?
A neutron is made of 3 quarks, namely an up quark and two down quarks. It is this composition of quarks that cause it to have zero charge. (An up quark has a charge of 2/3 and down quarks have a charge of -1/3 - thus 2/3 + (-1/3 *2) = 0) A free neutron (that is one that is not bound in a nucleus) will become a proton, an electron and an electron-neutrino. This happens through the weak force (it acts on a down quark, turning into an up). This does not mean a neutron contains an electron. It does not. Yes, an electron appears when a neutron decays, but that electron does not exist in the neutron as an electron, but it does not.
Why the concept of nuclear cross section is so frequently used in nuclear physics?
A nuclear cross section is a "technical" way of saying how large a "target" a given atomic nucleus presents to an incoming neutron. And we need to know that about different elements, and about the different isotopes of those elements. There are some other applications, but this is the "biggie" for the use of the term nuclear cross section. And we need to start with the idea that fission begins with a neutron entering an atomic nucleus to cause fission. If your model of nuclear fission is a cue ball breaking a rack of billliard balls, we need to refine it. Get you from the "B" grade to an "A" grade in physics. A neutron doesn't "smash" an atomic nucleus. It is captured by it (neutron capture) and an instability results. A neutron released in the fission process comes away from the fission event like a bullet out of a gun. Because it is moving so "fast" it has a low probability of being captured. It needs to undergo some scattering (little "collisions" with other atomic nuclei) to slow it down (thermalize it). The thermal neutron has a higher probability of being captured by a given nucleus and causing another fission, if it is captured by a fissionable atom. We've seen how the energy of the neutron affects its probability of being captured, but it turns out that different elements present a different sized "target" for the neutron. The size depends on the energy of that neutron, but also on the element being targeted, and which isotope of that element is under consideration. To repeat, each element has a different nuclear cross section (target size) for a neutron (of a given energy), and each isotope of a given element has a different nuclear cross section (for that same given neutron energy). Three things are at work. The energy of the neutron aside, the element and the different isotopes of each element have different probabilities of capturing a neutron of a given energy. The nuclear cross section is a measure of the "receptivity" of a given nucleus to an incoming neutron. It's that probability of capture. That's it in a nutshell. Links can be found below.
