What are Nucleons in Chemistry?
In both Chemistry and Physics, a nucleon can be either a proton or a neutron, Its role is considered as a component of an atomic nucleus. The number of nucleons in a nucleus describes the mass number of an isotope.
They are also known to be composite particles that are made of three quarks bound together by a strong interaction. The strong interaction between two or more nucleons is called inter-nucleon interaction/nuclear force, which is also finally caused by the strong interaction. Also, before the discovery of quarks, the term "strong interaction" was referred to as just internucleon interactions.
What are Nucleons?
A nucleon is one of the subatomic particles of the nucleus of an atom. Each atomic nucleus can contain one or more Nucleons and these nucleons are surrounded by one or more electrons.
Nucleons occupy a very small space within the nucleus. Each and every atom is made up of nucleons which are then divided into particles viz: electrons, protons, and neutrons that orbit the nucleus.
We can imagine an atom like a mini solar system with electrons orbiting a central star which is the atomic nucleus, made up of nucleons. We can see the image below:
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Nucleon Definition
Nucleon, is either of the subatomic particles, viz: the proton and the neutron, residing in the atomic nuclei. Protons are positively charged subatomic particles and neutrons are uncharged that behave identically under the influence of the short-range nuclear force, both in the way these subatomic particles are tightly bound in atomic nuclei and in the manner they are scattered by each other.
This strong interaction between these particles is independent of electric charge. Unstable subatomic particles are heavier than nucleons that are hyperons and baryon resonances and they comprise a nucleon among their final decay products; the nucleon is, therefore, the baryon ground state. The antinucleons are of two types viz: the antiproton and the antineutron.
Types of Nucleons
Primarily, there are two types of nucleons viz: protons and neutrons. A proton carries a positive electric charge, and a neutron has a neutral electric charge, which means that it bears no electric charge on it. These two particles reside in the nucleus of the atom and generate a positive charge because the neutron has no charge at all.
We must note that protons and neutrons are the only best-known components of atomic nuclei so far. These two particles can be found on their own not being part of the larger nucleus (residing inside it).
Point to Remember
A particle viz: the proton is the nucleus of the hydrogen-1 atom on its own which is considered the most abundant isotope of hydrogen.
So, whatever particles that reside in the nucleus are nucleons; however, electrons revolve around the nucleus, so it is not considered nucleons.
Binding Energy of a Nucleon
As we know, a nucleus consists of neutrons and protons; however, the mass of the nucleus is less than the sum of individual masses of the proton and the neutron. The difference lies in the measurement of binding energy per nucleon that tightly holds nucleons. The binding energy can be determined by Einstein’s equation. The relationship is as follows:
Nuclear binding energy = ∆mc2
Here,
∆m = mass of a nucleon
c = speed of light, i.e., 3.8 x 108 m/s
Since Δm for alpha particles is 0.0304 u (unit), this gives us the binding energy of a nucleon as 28.3 MeV.
What is a Nucleon?
So far we have been studying that a neutron is not a stable particle residing in an atom, but it can be used in nuclear reactions and scientific analysis. Protons and neutrons consist of three quarks. The proton has two up quarks, which is the lightest of all quarks and a major constituent/portion of matter and a type of elementary/fundamental particle and one down quark, which is the second lightest quark, while a neutron is composed of one up quark and two down quarks.
These up and down quarks composed of protons and neutrons are an integral part of the atomic nucleus because they cannot persist as independent nucleons. The atomic nucleus holds the nucleons with a strong force of attraction. However, when the force is broken, a lot of power is generated and that power is termed nuclear energy which is similar to what we use in the production of nuclear bombs.
One must be very careful and understand that nucleons present in radioactive decay substances such as Uranium can be harmful since they can spread alpha radiation in a fraction of seconds.
All about Nucleon: Attributes
Composition of Nucleus: The nucleus is made up of protons and neutrons that are collectively called nucleons.
Nuclear charge: The nucleus comprises protons and neutrons.
Nuclear mass: We call the mass of the nucleus a nuclear mass.
Nuclear Size and shape: The nucleus is considered nearly spherical in shape.
FAQs on Nucleons
1. What are nucleons in chemistry?
A nucleon is a particle found within the atomic nucleus. The term is a collective name for either a proton or a neutron. These particles are responsible for nearly the entire mass of an atom and are bound together by the strong nuclear force.
2. What are the two types of nucleons?
The two fundamental types of nucleons that constitute the atomic nucleus are:
- Protons: These are subatomic particles that carry a positive electric charge. The number of protons determines the atomic number (Z) of an element.
- Neutrons: These are electrically neutral particles with a mass slightly greater than that of protons.
3. What is the main difference between a nucleon and a nucleus?
The primary difference lies in their scale and composition. A nucleon is a single constituent particle (one proton or one neutron), whereas the nucleus is the entire structure at the center of an atom, which is composed of all the atom's nucleons.
4. How do nucleons differ from nuclides?
While related, these terms describe different concepts. A nucleon is a building block of the nucleus (a proton or neutron). In contrast, a nuclide refers to a specific kind of atomic nucleus, defined by its unique number of protons and neutrons. For example, Carbon-12 and Carbon-14 are different nuclides, but both are constructed from nucleons.
5. What is the significance of the mass number of an atom in relation to its nucleons?
The mass number, represented by the symbol 'A', is the total count of all nucleons in an atomic nucleus. It is calculated by adding the number of protons (Z) to the number of neutrons (N). The mass number is crucial as it directly indicates the total mass of the nucleus and helps identify specific isotopes of an element.
6. How does nuclear binding energy relate to the stability of nucleons within a nucleus?
Nuclear binding energy is the energy that holds nucleons together. It originates from the mass defect, where the mass of a nucleus is less than the sum of the individual masses of its nucleons. This 'lost' mass is converted into energy (per E=mc²), which stabilizes the nucleus. A higher binding energy per nucleon signifies a more stable and tightly bound nucleus.
7. What are nucleons themselves made of?
Nucleons are not fundamental particles; they have an internal structure. Each nucleon is a composite particle made of smaller elementary particles called quarks. A proton is composed of two 'up' quarks and one 'down' quark, while a neutron is made of one 'up' quark and two 'down' quarks.
8. What is the nature of the nuclear force that holds nucleons together?
The nuclear force is a fundamental interaction that binds protons and neutrons. Its key characteristics are:
- It is the strongest known force in nature.
- It is extremely short-ranged, acting only within the diameter of the nucleus.
- It is charge-independent, affecting proton-proton, neutron-neutron, and proton-neutron pairs equally.
9. Why are electrons not considered to be nucleons?
Electrons are not classified as nucleons because the term 'nucleon' specifically refers to particles that reside inside the atomic nucleus. Electrons are fundamental particles called leptons that orbit the nucleus. They are governed by the electromagnetic force, not the strong nuclear force that binds protons and neutrons together.
