Neutron What is it?

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  1. Neutron
    1. Definition of Neutron
    2. Neutron Discovery
    3. What are neutron stars? (Astronomy)
    4. Neutron details
    5. Nuclear fission
    6. Uncontrolled reaction
    7. What is Neutron? A simple answer
    8. Key facts about neutrons
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A neutron is a subatomic particle contained in the atomic nucleus. It has no net electrical charge, unlike the proton which has a positive electrical charge.


The number of neutrons in the atomic nucleus of an element determines the isotope to which it belongs. Neutrons, together with protons, form atomic nuclei.

The neutron interacts with protons through strong nuclear force, but without electromagnetic repulsion, since its electrical charge is zero.

Neutron is present in almost all atomic nuclei. The only exception is hydrogen that has no neutrons in its nucleus.

Outside the atomic nucleus, the neutron is unstable and has a half-life of about 15 minutes. When it disintegrates, it emits an electron and an antineutrino, after which it becomes a proton.

The half-life of the neutron outside the atomic nucleus is fifteen minutes when it emits an antineutron and an electron to become a proton.

Those neutrons that have a mass similar to that of protons are necessary for the stability of atomic nuclei, with the exception of hydrogen.

To know how many neutrons an atom has, subtract the atomic mass with the atomic number. For example:

The atomic number of vanadium is 23 and its atomic mass is 51:
The vanadium atom has 28 neutrons.

Definition of Neutron

Neutrons. They are electrically neutral particles, with a mass 1,838.4 times greater than that of the electron and 1,00014 times that of the proton; together with protons, neutrons are the fundamental constituents of the atomic nucleus and are considered as two forms of the same particle: the nucleon.

The neutron is a particle without net charge, present in the atomic nucleus of practically all atoms, except the protium.

Although the neutron is said to have no charge, it is actually composed of three charged fundamental particles called quarks, whose charges are zero when added together.

Therefore, the neutron is a neutral baryon composed of two quarks of type below, and a quark of type above.

Outside the atomic nucleus, neutrons are unstable, having a half-life of 15 minutes (885.7 ± 0.8 s), each neutron being broken down into an electron, an antineutrino, and a proton. Its mass is very similar to that of the proton, although slightly larger.

Neutron is necessary for the stability of almost all atomic nuclei except for the hydrogen-1 isotope. Strong nuclear interaction is responsible for keeping them stable in atomic nuclei.

Neutron Discovery

The first indication of the existence of neutron occurred in 1930, when Walther Bothe and Becker, H. found that when alpha radiation fell on elements such as lithium and boron a new form of radiation was emitted.

Initially, this radiation was believed to be a type of gamma radiation, but it was more penetrating than any known gamma radiation.

The work was done by Irene Joliot-Curie and Joliot Frederic in 1932, although it does not refute the hypothesis of gamma radiation, does not support everything well.

In 1932, James Chadwick demonstrated that these results could not be explained by gamma rays and proposed an alternative explanation of uncharged particles about the same size as a proton.

Chadwick was able to experimentally verify this conjecture and thus prove the existence of the neutron.

Neutrons are fundamental in nuclear reactions: when a neutron strikes a fissile atom, a greater number of neutrons are produced, which in turn cause other chain fission.

If this reaction takes place in a controlled way by using a moderator in the nuclear reactor, it is possible to take advantage of the nuclear energy developed.

What are neutron stars? (Astronomy)

A high mass star becomes a black hole. But in between, a star becomes a neutron star.

In this video, we talk about which stars become neutron stars, and the physics behind their formation.

Neutron details

The neutron is made up of three quarks, one quark up and two quarks down.
The mass of the neutron is slightly greater than that of the proton.

The neutron does not exist outside the length of the atomic nucleus, only a mere 885 seconds (15 minutes) on average.

  1. Mass: 1.67492729 × 10-27 kg
  2. Load: 0
  3. Spin: 1/2

Because the neutron has a 1/2 spin, it is a fermion.

Nuclear fission

The fundamental process leading to the production of nuclear energy is the fission of a neutron-originated uranium nucleus: in fission, the nucleus is split into two parts and about three neutrons on average (fast neutrons); the fragments resulting from excision emit other neutrons as well.

Neutrons are fundamental in nuclear reactions: a chain reaction occurs when a neutron causes the fission of a fissile atom, producing a greater number of neutrons which in turn cause other fission. Depending on whether this reaction takes place in a controlled or uncontrolled manner, the following occurs:

Uncontrolled reaction

is only produced when there is a sufficient quantity of nuclear fuel - critical mass - the basis of the nuclear bomb.

Controlled reaction: through the use of a moderator in the nuclear reactor; basis for the use of nuclear energy.

What is Neutron? A simple answer

The essential nature of the atomic nucleus was established with the discovery of the neutron by James Chadwick n 1932

The discovery of the neutron causes a lot of impact on the world which finally led the world to create nuclear power and nuclear weapons.

Key facts about neutrons

Neutrons are found in the nucleus of atoms, along with protons in the atom.
Neutrons have zero charges. Another way to say the same thing is that neutrons are neutral.

Neutrons have a relative mass of 1, which is the same as the relative mass of protons.
The number of neutrons in an atom can be calculated from the atomic number of that atom (element) and the number of a mass of that atom (isotope).

Number of neutrons (in an atom) = mass number (A) - atomic number (Z).

  1. Protons and neutrons are called nucleons.
  2. Neutrons are responsible for almost half the weight of conventional matter by volume.
  3. Neutrons play important roles in the production of nuclear energy.

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