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240Pu decays to 236U by emitting an alpha particle. You can tell this by looking at the difference in Atomic Mass. 240 minus 236 is 4, and that is the mass of an alpha particle. You can also tell this by looking at a chart of the nuclides. See the related link below for an example from Brookhaven National Laboratories.
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When a unstable radioactive atom degrades what happens to it?
You probably mean decays, not degrades. When an unstable atom decays it goes through one of the following processes:Alpha decay - a helium nucleus is ejected reducing the element number by 2 and the mass number by 4.Beta decay - a neutron decays to a proton, electron, and a neutrino. The electron and neutrino are ejected increasing the element number by 1 and leaving the mass number constant.Gamma decay - the protons and neutrons in the nucleus rearrange themselves into a lower energy state and a gamma ray photon is ejected to remove the excess energy. Neither the element or mass numbers change.Fission - certain transient metastable isotopes (e.g. U236 produced by U235 capturing a neutron) can split into two smaller nuclei and eject 2 or more neutrons. Note: Fission is not usually considered a decay process.
What is produced when uranium nuclei is bombarded with neutrons?
This depends on a lot of things. When a neutron collides with an uranium atom, it might bounce off, cause the atom to decay, or be captured into the atom. But which it does depends on the isotope of the atom, the temperature of the atom, and the velocity of the neutron. My understanding is that it can cause any isotope of uranium to decay, and certainly it can bounce off any, but it can only be captured by U233, U234, or U235; the other isotopes of uranium, U236, and U238, will not capture neutrons. The interactions of various isotopes of different temperatures with neutrons of different velocities is complicated, and no simple rule about it can be stated.
Fission is the process of creating energy by?
On nuclear fission, small fraction of mass is loss and transform to energy. The loss mass is part of tiny sub-atomic particle. Consider reaction of Uranium U235 + n1 --> U236 --> Kr92 + Ba141+3n1 Well seem all mass is balance. But take careful step U235 is 235.0439 U236 is 236.0526 Kr92 is 91.92616 Ba141 is 140.9144 n is 1.008665 Some mass was lost and that mass go to energy as Einstein state E = mC2
When a unstable radioactive atom degrades what happens to it?
You probably mean decays, not degrades. When an unstable atom decays it goes through one of the following processes:Alpha decay - a helium nucleus is ejected reducing the element number by 2 and the mass number by 4.Beta decay - a neutron decays to a proton, electron, and a neutrino. The electron and neutrino are ejected increasing the element number by 1 and leaving the mass number constant.Gamma decay - the protons and neutrons in the nucleus rearrange themselves into a lower energy state and a gamma ray photon is ejected to remove the excess energy. Neither the element or mass numbers change.Fission - certain transient metastable isotopes (e.g. U236 produced by U235 capturing a neutron) can split into two smaller nuclei and eject 2 or more neutrons. Note: Fission is not usually considered a decay process.
What is the process in which an unstable nucleus loses energy spontaneously?
Particles or electromagnetic radiation are emitted.
How much energy is required to remove a neutron from ground state U-236 to make it U-235?
It is unclear exactly how a single neutron could be removed from a Uranium-236 nucleus to create a Uranium-235 nucleus. (It would probably prove quite difficult to do.) As to the energy required to do this, about all we can do is look at the binding energy of this nucleus. It turns out that the binding energy per nucleon in the U236 nucleus is about 7.6 MeV (million electron volts). This suggests that it would take a minimum of about 7.6 MeV to pluck that neutron from the U236 nucleus to create the U235 nucleus.
What is the principle of a nuclear reactor?
how the nuclear reactor can work? A nuclear reactor is a system which generates a nuclear fission reaction. A nuclear reaction is a self-sustaining reaction where the output of one stage is the input of the next stage. Therefore, if there is enough fuel, the reaction will continue indefinitely. The most common type of fission reaction is a Uranium 236 reaction. Nuclear fission involves splitting an atom into smaller atom(s). In a U236 reaction, Uranium 235 is the fuel. A neutron is propelled, which strikes the nucleus of a Uranium 235 atom, creating a U236 atom. U236 is highly unstable, and undergoes radioactive decay. This means the U235 atom turns into a Krypton atom, and a Barium atom, plus 2 extra neutrons and some energy. This energy is generally heat, and is absorbed by nearby water, which boils and turns a turbine. The two neutrons continue the reaction by hitting another U235 atom (each). There are other types of nuclear reactions as well, but the principle is the same. The output is generally atoms of different atomic mass, energy, and some other byproduct which will continue the reaction (e.g. an alpha particle - a Helium nucleus, or a neutron). In nuclear fission, the atom byproducts have a lower atomic mass. In nuclear fusion, the atom byproducts have a higher atomic mass (since multiple atoms are fused together). Nuclear fusion is the basic power plant in the core of the sun (combining Hydrogen atoms into Helium, or Helium into Carbon, etc.). The byproduct here is the energy that we see as light. Slow neutron fission chain reaction.
What is produced when uranium nuclei is bombarded with neutrons?
This depends on a lot of things. When a neutron collides with an uranium atom, it might bounce off, cause the atom to decay, or be captured into the atom. But which it does depends on the isotope of the atom, the temperature of the atom, and the velocity of the neutron. My understanding is that it can cause any isotope of uranium to decay, and certainly it can bounce off any, but it can only be captured by U233, U234, or U235; the other isotopes of uranium, U236, and U238, will not capture neutrons. The interactions of various isotopes of different temperatures with neutrons of different velocities is complicated, and no simple rule about it can be stated.
Why is energy released when nuclear reactions take place in the reactors of nuclear power plants and in the sun?
Because of a change in mass. The same story for fusion, like in the sun: with enough energy, two Hydrogen atoms can be brought close enough together to overcome the electrical repulsion (2 positively charged particles naturally want to repel each other), that they fuse together and form Helium and also release a couple neutrinos and 6 gamma ray photons. The release of energy actually comes from the change in mass (the resultant Helium is actually slightly less massive than the two Hydrogen atoms). The sun also fuses other elements, but only those less massive than Iron. Any element heavier than Iron requires, rather than releases, energy. In fission occurring in a nuclear reactor, when uranium splits into the smaller elements there is actually a small decrease in mass. This change in mass is released as energy, according to the equation E=mc^2 A thermal (slow, in technical terms) neutron shot at Uranium 235 falls into the potential well associated with the strong forces of the nucleus. U235 is initially 245.043922u, the neutron is 1.008664u, and the resulting U236 is only 236.045562u. The resulting mass is lacking 7.024x10^-3 u. The energy released, according to E=mc^2, is 6.5 MeV. U236 is unstable, however, and after oscillating for a time it splits into two smaller elements such as Kr and Ba, at which time more particles and energy is released.
