The neutron is a subatomic particle, symbol n or n0, which has a neutral (not positive or negative) charge, and a mass slightly greater than that of a proton. Protons and neutrons constitute the nuclei of atoms. Since protons and neutrons behave similarly within the nucleus, and each has a mass of approximately one atomic mass unit, they are both referred to as nucleons. Their properties and interactions are described by nuclear physics.
The chemical properties of an atom are mostly determined by the configuration of electrons that orbit the atom's heavy nucleus. The electron configuration is determined by the charge of the nucleus, which is determined by the number of protons, or atomic number. The number of neutrons is the neutron number. Neutrons do not affect the electron configuration, but the sum of atomic and neutron numbers is the mass of the nucleus.
Atoms of a chemical element that differ only in neutron number are called isotopes. For example, carbon, with atomic number 6, has an abundant isotope carbon-12 with 6 neutrons and a rare isotope carbon-13 with 7 neutrons. Some elements occur in nature with only one stable isotope, such as fluorine. Other elements occur with many stable isotopes, such as tin with ten stable isotopes.
The properties of an atomic nucleus depend on both atomic and neutron numbers. With their positive charge, the protons within the nucleus are repelled by the long-range electromagnetic force, but the much stronger, but short-range, nuclear force binds the nucleons closely together. Neutrons are required for the stability of nuclei, with the exception of the single-proton hydrogen nucleus. Neutrons are produced copiously in nuclear fission and fusion. They are a primary contributor to the nucleosynthesis of chemical elements within stars through fission, fusion, and neutron capture processes.
The neutron is essential to the production of nuclear power. In the decade after the neutron was discovered by James Chadwick in 1932, neutrons were used to induce many different types of nuclear transmutations. With the discovery of nuclear fission in 1938, it was quickly realized that, if a fission event produced neutrons, each of these neutrons might cause further fission events, in a cascade known as a nuclear chain reaction. These events and findings led to the first self-sustaining nuclear reactor (Chicago Pile-1, 1942) and the first nuclear weapon (Trinity, 1945).
Free neutrons, while not directly ionizing atoms, cause ionizing radiation. So they can be a biological hazard, depending on dose. A small natural "neutron background" flux of free neutrons exists on Earth, caused by cosmic ray showers, and by the natural radioactivity of spontaneously fissionable elements in the Earth's crust. Dedicated neutron sources like neutron generators, research reactors and spallation sources produce free neutrons for use in irradiation and in neutron scattering experiments.
before i start i wanted to make it clear that this is NOT homework. its just a quick question which puzzled me and my friend
In the shell model of the nucleus. i found a statement that said that since both neutrons and protons are fermions, there are restricted to 2 of each at each energy...
do neutrons also feel strong nuclear force and if they do how is that possible because they are uncharched and no force is required to keep them together
?
An element of helium consists of 2 protons, 2 neutrons, and 2 electrons.
I have been told that anti-helium can exist if instead of 2 protons there are 2 antiprotons, instead of 2 neutrons there are 2 antineutrons, and instead of the 2 electrons there are 2 positrons. Is this true?
Also...
What would happen if you fired a neutron at neutronium? Would it become apart of the neutronium substance of would it shatter the neutronium substance if the velocity of the neutron particle were quick enough?
Thanks
F.L.
Ok so something been bother me about neutrons lately.
When want to move a bunch of neutrons from approx, point a to approx. point b, is around how do you it? I didn't yo couldn use a supwercollider since:
neutrons are neutrally charg; therefore, you cannnot move them with a intense electric...
I'm just wondering why it's important for atomic structures to contain protons. Hydrogen-3 has two neutrons and one proton. Could you have a particle with two or more neutrons held together by nothing but the strong nuclear force? Is the reason I don't know about this because such particles...
My professor told me that the neutrons in a reactor see the surface area of nuclei, and not the the projected cross section. That really doesn't make intuitive sense. Is he right?
I am aware that there is strong evidence for the presence of quarks inside of protons and neutrons through the analysis of deep inelastic scattering experiments.
The questions I have specifically relate to the data which supports the composition of the neutron versus the proton, how we have...
Homework Statement
A bar of copper has dimensions 0.5605 ft. x 3.545 in x 5.722 cm. The density of copper is 8.921 g / cm3. Copper contains 2 isotopes, 63Cu (69.09% abundant) and 65Cu (30.91% abundant). How many neutrons are in the bar of copper?
The attempt at a solution
I took the...
Sorry, this is probably a dumb question but I am new to physics so forgive my ignorance. I learned in class that when a person touches something, or any two objects touch each other for that matter, the force interaction is actually due to the electrons repelling each other. So I wondered what...
As I understand it, the magnetic field confines the electrons because of the repulsion of the electrons in the plasma and the electrons traveling in the magnetic current.
My question is what keeps the protons and neutrons released in the plasma from passing through the magnetic field in a...
If an nuclide can be fissioned by thermal neutrons does that always mean it can be fissioned by fast neutrons. If not how can one tell this by looking at the neutron cross section?
The nuetron has a known substructure of three charged quarks with net charge 0. Still, these quarks cannot occupy the same space simultaneously, so neutrons should have an electric field surrounding them.
Has any work been done to find the properties of this field? For example, what is the...
U-235 is most suitable for bombardment by slow neutrons 'cause it becomes U-236,providing for a more balanced nucleus. So if the electron shells are arranged something like 2,4,8,16,32,18,8,2 the atomic number only changes, in this case, because of an additional neutron. Is this element in a...
Neutrons bind Protons in nuclei, and/or the other way around, but why don't
Neutrons bind Neutrons, with clumps of neutrons whizzing about?
And, I'm guessing this is related: Why is a Neutron unstable outside
its nucleus with about a 10.3 minute half-life?
I am wondering about something:
Calculate the Fermi energy for the neutrons confined to a nucleus with 40 protons and 50 neutrons which roughly forms a sphere of radius 4.6 10^(-15) m.
the formula of the fermi Energy is EF= ((h-bar)^2*(3*pi^2*n)^(2/3))/2m
m:mass of electron, n = number...
Homework Statement
You have 10 protons and 10 neutrons to paly with (mass of oxygen = 15.994915)
a. What is the mass of an oxygen nucleus that you build with equal numbers of protons and neutrons?
b. What is the binding energy of this nucleus?
Homework Equations
E=mc^2...
I have a very basic question regarding the nucleus.
I understand why you can only have a limited number of protons within the nucleus - more and more protons within the nucleus will increase the coulomb potential and cause the nucleus to be unstable.
But why is this so for neutrons? Why...
Homework Statement
At very high temperatures (as in the early universe), the proton and the neutron can be thought of as two different states of the same particle, called the “nucleon”. (The reactions that convert a proton to a neutron or vice versa require the absorption of an electron or a...
First of this is not an homework question but just a bit of a theory i am having a bit of difficulty understanding. Secundly, hello!
James Chadwick discovered neutrons by sending alpha-particles from a radioactive source to a beryllium-plate, and that plate then sent out neutrons.
I don't...
Question:
The postulate that mass attracts mass is present in both the classical description of gravity and GR. My question is related to the extra nuetrons in heavy atoms, if there is experimental evidence that these extra neutrons are also part of the equation.
I wish to read about...
Hey guys this is my first post on Physics Forums, be gentle.
I've been wondering, what's the current explanation of why protons and neutrons have such very similar masses? Is this due to a difference in the up and down quark masses or is there something else going on here?
Thanks
Atomic wieght...
I know, or at least think the wieght of an atom is the number of neutrons...but what I want to know is what governs this number? Is it a gravitational force...I mean all this spinning going on...how can they be so small, so close together and not bump into each other?--what...
An isotropic point source of neutrons emits 10E8 fast neutrons per second. It is 3m horizontally away from a train track. A train goes by at 60 miles per hour. Ignoring scattering and attenuation, what is the fluence (i.e. neutrons per meter square) of neutrons that would strike a pasenger at...
My textbook said that only lower energy neutrons (around 1ev) favor Uranium fission while higher energy neutrons don't. Is there an explanation for this. ( i don't think we are required to know it for the course but I'm just interested...)
Thanks.
Problem
One thousand neutrons are in a one-dimensional box, with walls at x = 0, x = a. At t = 0, the state of each particle is
\psi(x, 0) = Ax(x-a)
a) Normalize \psi and find the value of the constant A.
b) How many particles are in the interval (0, a/2) at t=0?
c)How many particles...
Hi all.
Why does Uranium-238 absorb fast moving neutrons very well but not slow moving ones?
My intuition tells me it should be the other way around but its not.
Thanks.
Quick question, regarding mass-energy equivalence (e=mc2) and matter creation.
Knowing that there are many concete visual examples of matter turning into energy using Einstein's equation, how do you use energy to create matter? If I'm not mistaken, I believe electron-positron pairs are...
Before you go on: I had no idea were to actually post this, as I found no other good forums on the net where you could discuss physics. If a mood locks or moves this topic, I fully understand. Please don't flame the thread though. Leave that to the mods :)
After playing the game Mutants and...
Is possible some elements (like Cadmium or Bohr) absorb neutrons, without any nuclear reaction in their atomic nucleus? If the answer is YES, then why there isn't any nuclear reaction?
1. I have ^{9}Be^{+}, ^{12}C, and ^{15}N^{+++} isotopes, and I need to find the total of protons, neutrons, and electrons.
A = Z + N, where A is the atomic mass number and Z is the number of protons and N is the number of Neutrons.
3. I know this is an easy question, I put it in physics because...
How does deuterium interacts with neutrons? I sow in nuclear power plants is used heavy water, and it says because the heavy water interacts with neutrons? Is it mechanically stopping them, or there is some other kind of interaction?
btw- how neutrons in deuterium stick together, how they are...
Sorry if this is a really easy question, but in biology I don't normally deal with these matters, just confused about this.
Why is it that the mass of the electron is so much smaller than that of the proton or neutron, but the charge is similar to the proton (but opposite)? I'm assuming it has...
My question is about the formation of a neutron star once fussion stops and it collapses. I recently saw a show about the life of a star and it said when gravity overcomes the energy released by fussion, the electrons are compressed toward the nucleus of the atoms and create neutrons. I...
Homework Statement
Canadian nuclear reactors use heavy water moderators in which elastic collisions occur between neutrons and deuterons of mass 2.0u.
a.) What is the speed of a neutron expressed as a fraction of its original speed, after a head-on elastic collision with a deuteron which is...
Homework Statement
state the number of protons electrons and neutrons of these:
Magnesium-25
Cu-65
Homework Equations
protons is the same as atomic numbber, same with electrons. NEUTrons is atomic number - atomic mass
The Attempt at a Solution
Magnesium-25 Cu-65...
Hi,
We were told in a very-elementary elementary particles course, that a neutral current event was first observed in the following process:
\bar{\nu}_\mu + n \longrightarrow \bar{\nu}_\mu + X
were X is "something other than muon" (n was a neutron).
I thought about it, and I don't know how X...
Hi all,
I have a question, which sounds somewhat silly, but I'm stuck with it. I'm writing some monte carlo code to simulate the effect of multiple hits on neutron detectors, and I'm confronted with the following issue.
Consider a "multiple hit" of a detector. That means, a neutron impact at...
When neutrons come together energy is emitted.If there are a lot of neutrons close together in a ball,will the energy emitted by the neutrons at the centre of the ball push the neutrons nearer the surface out of the ball?
According to a textbook that I was looking at, electron capture and electron-proton collisions both produced a neutron and an antineutrino, but one was mediated by a W+ particle and the other by a W-. Is this correct, or are they interchangeable?
Hi, I was wondering if anyone could give me a simple description on what nuclear power is. I.e. how the neutrons from UO2/U/PuO2 are harnessed for power?
Also, if anyone knows any useful links for information on nuclear power, different types of ractors etc, then it will be very useful :smile: