What is strong nuclear force and what does it affect?

Answer 1

The strong nuclear force (nuclear binding energy) holds atomic nuclei together, and it must be very strong to overcome the tendency for protons to repel each other. Protons, as you'll recall, are positively charged, and like charges repel. Another issue with the strong force is that it only acts between objects made of quarks, in this case protons and neutrons. Since neutrons have no electric charge, you may add more neutrons to a nucleus (up to a point) to help hold the whole thing together. This is because the protons will be bound to the neutrons by the strong force, and protons and neutrons will not repel each other. For reasonably light elements, it's often most efficient to add one neutron for each proton, and that is why elements like carbon have 6 protons and 6 neutrons. As we move up through larger atomic numbers, the neutron-to-proton ration increase above one to one. For heavier elements like 235Uranium, we see a nucleus that has many more neutrons than protons, 143 neutrons to its 92 protons. Though the strong force can overcome the electrostatic forces within a nucleus, it has a very short range. In fact, its main work is in holding the constituent quarks of the protons and neutrons together. Only the little bit of the strong force that "leaks" out actually holds protons and neutrons together (like van der Waals force between neutral atoms). The binding energy (or nuclear glue) is termed residual strong force for this reason. Since its range is so short, approximately only able to hold a particle to its next nearest neighbors, when a nucleus gets too large, it eventually can't be held together in a stable configuration. The electrostatic repulsion of the protons will eventually overcome the total nuclear binding energy and "large" atomic nuclei won't be able remain stable. That's why we see (with the rarest exception) the lack of any stable isotopes of elements at the upper end of the periodic table. Eventually we'll see nothing but radioactive isotopes for elements, and they'll have different decay modes including spontaneous fission. The electrostatic forces win out over the nuclear binding energy in these largest nuclei and they're uniformly unstable.

Answer 2

The strong nuclear force holds atomic nuclei together, and it must be very strong to overcome the tendency for protons to repel each other. Protons, as you'll recall, are positively charged, and like charges repel.

Answer 3

Protons are positively charged, and we know that like charges repel each other. The protons in the nucleus of an atom are trying to push each other away. But the residual strong force, or nuclear binding energy (nuclear glue) holds the atomic nucleus together. The two forces (residual strong force and electrostatic force) are struggling in a standoff inside every nucleus of every atom (except hydrogen-1). Some atomic nuclei are stable, and some are not, but in all cases, the two forces are at odds with each other in a nucleus. In radioactive (unstable) nuclei, the repulsive forces eventually win and the atom undergoes radioactive decay. We can find examples of unstable isotopes in nature or in the physics lab where we make them to study them. In the heaviest nuclei, the ones of the elements at the upper end of the Periodic Table, there are no stable isotopes, and they all exhibit radioactive properties and decay. This clearly demonstrates the limit of the ability of the nuclear binding energy (residual strong force) to overcome the electrostatic repulsion of all those protons in the nucleus. No element heavier than bismuth has any stable isotopes. And when we look at elements that we've synthesized that have atomic numbers in the high double digits and in the triple digits, we just don't see anything that stays around for more than a very brief period. The residual strong force holding a nucleus together and the electrostatic force repelling the protons in an attempt to force that nucleus apart are in an eternal struggle for dominance. In some cases the isotope under inspection decays, and the nuclear binding energy has failed. In other cases, the nucleus is stable, and the electrostatic repulsion is held in check permanently by the residual strong force.

Answer 4

"Strong nuclear force" is a misuse of terminology. The correct term is "strong atomic force".

The strong atomic force, also known as the strong force, also known as binding energy, is, in the sub-sub-atomic scale, the strongest force in the universe. It is stronger by about a factor of 100 than the electromagnetic force, and it is stronger by many, many orders of magnitude than the weak atomic force, and many, many, many more orders of magnitude than gravity.

The strong atomic force hold quarks together to form protons and neutrons. As stated above, it overcomes the electromagnetic force that would tend to cause like quarks (up versus up, and down versus down) to repel each other.

Not part of the question, but answered for completeness... Down quarks have a charge of -1/3, while up quarks have a charge of +2/3. Two down quarks and one up quark form a neutron with a net charge of zero, while one down quark and two up quarks form a proton with a net charge of +1.

The residual strong atomic force left over from holding quarks together to form neutrons and protons goes into holding neutrons and protons together to form atomic nuclei. This residual strong atomic force is also known as the nuclear force, but there is no "strong" in that usage. It is also known as residual binding energy.

Part of this residual binding energy is what is released during nuclear fission and nuclear fusion, and is represented by Einstein's famous mass-energy equivalence equation e = mc2. This is due to the fact that when you split an atom, or fuse two atoms, the residual binding energy required to sustain the result(s) is less than was required to sustain the original.

Here's where it gets interesting...

You have the strong force holding quarks together, and the nuclear force holding protons and neutrons together, both of which are based on the same thing, and both of which are stronger than the electromagnetic force which is trying to blow everything apart.

Well, it turns out that both the nuclear force and the electromagnetic force are based on distance.

Actually, so is the strong force, but within the narrow confines of the definition, i.e. being within the proton or neutron, it does not matter.

The issue is that the nuclear force decreases faster with distance than does the electromagnetic force, and it does so within the confines of the size of the larger nuclei, specifically those that are greater that atomic number 82, i.e. lead.

Up to lead, with the exception of various isotopes, such as carbon-14, which are unstable for other reasons, all of the smaller nuclides, with certain "magic" neutron/proton ratios are stable, because the nuclear force is greater than the electromagnetic force.

Starting at atomic number 83, bismuth, however, the size of the nucleus starts to make the electromagnetic force win out over the nuclear force. This makes the nucleus unstable. No nuclide from bismuth on up is stable. They are all radioactive.

Answer 5

Nuclear forces are short range forces and are effective within the nucleons. Only the positive charge of nucleus is effective for electrons around the nucleus.

Answer 6

It keeps the nucleus together, despite the fact that the protons tend to repel one another via the electric force. But in the case of existing atoms, the nuclear force is stronger.

Answer 7

The protons.

Answer 8

Protons