Neutrons: Introduction, Mass, Charge, How to Find Neutrons, Discover, Properties & Uses

Neutrons are subatomic particles found in the nucleus of an atom, just like protons. Neutron does not have any charge and is a neutral particle. They have a mass equal to the mass of hydrogen atoms and slightly greater than the mass of protons. Neutrons along with protons known as nucleons are bound together in the dense inner core of an atom, the nucleus, where they account for 99.9 per cent of the atom’s mass. All the elements except hydrogen have neutrons. 

In this Chemistry article, learn about neutrons, their mass, charge, how to find neutrons, their discovery, properties and uses of neutrons.

Neutrons 

Neutrons are electrically neutral particles having a mass slightly greater than the mass of protons. Neutrons are denoted using the symbol , the zero superscript n, representing the neutrality of these particles. It is discovered that a neutron is not a true elementary particle. Neutron is composed of the smallest known elementary particle called quarks. Neutron is composed of two down quarks, each having ⅓ elementary charge, and one up quark, with ⅔ elementary charge. Neutrons and protons are held together in the nucleus by the residual effect of the strong force, the strongest known fundamental force. 

Mass of Neutron

The mass of neutrons can be detected using mass spectroscopy. The mass of a proton and deuteron can be measured using a mass spectrometer, then by subtracting mass of proton from deuteron mass, with the difference being the mass of the neutron plus the binding energy of deuterium, the mass of the neutron can be calculated. The formula for calculating the mass of a neutron is given as-

Here, = mass of neutron

= mass of deuteron

= mass of proton

= binding energy of deuterium

= recoil kinetic energy

Let's see the mass of neutrons in amu and kg. 

Mass of Neutron in amu

The mass of a neutron in amu is 1.008665 amu, which is approximately equal to 1 amu. 

Mass of Neutron in kg

When the mass of a neutron in amu is converted to kg, it is approximately equal to .

Neutron Charge 

The neutron is a neutral particle, which means the charge on it is zero. A UW physics professor, Prof. Miller, found that a neutron has a negative charge on it’s inner core as well as its outer edge and a positive charge is sandwiched in between the two negative charges to make the particle electrically neutral.

How to Find Neutrons

The atomic mass of any element is equal to the sum of the number of neutrons and protons present in the element. Mathematically, 

Atomic Mass = Number of Neutrons +Atomic Number( N )(A=Z+Number of Neutrons)

Therefore, the number of neutrons in an element can be found by subtracting the number of protons from the mass of the element.

 Number of Neutrons = Atomic Mass - Number of Protons

Discovery of Neutron

Neutron was discovered by British physicist James Chadwick in 1932, he conducted an experiment in which he bombarded Beryllium with alpha particles from the natural radioactive decay of Polonium. In this experiment, he made the discovery of neutrons. For this discovery, he was awarded with the Nobel Prize in Physics. 

Properties of Neutron 

The characteristic properties of neutrons are-

• It is a neutral particle. 
• The mass of a neutron is 2000 times the mass of an electron.
• The weight of a neutron is 1 amu.
• The neutron possesses some magnetic field.
• They have a high penetrating power. 
• It is composed of three elementary particles called quarks. 

Uses of Neutron

The uses of neutrons are-

• Neutrons are used for research in medicines, materials and other fields. 
• Neutrons are used for developing new and better computer chips, cosmetics, detergents, textiles, paints, fuels, drugs, batteries, nanotechnology and plastics. 
• Neutron scattering is used to calculate a material’s properties, such as the shape and sizes of crystals and molecules. 
• The penetrating power of neutrons and their uniquely non-destructive nature helps with non-invasive testing on an atomic scale to investigate residual stress, deformation, and the microstructure of engineering components. 
• The study of neutrons and their reactions have a vital role in nuclear reactors and the development of nuclear weapons. 
• They are used for NAA i.e. Neutron Activation Analysis. It is used for analyzing samples in nuclear reactors.
• It is used in cancer treatments to cure cancer using boron capture therapy which uses a small beam of neutrons.

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