Question

Nucleons are:
(A) Protons and electrons
(B) Protons and neutrons
(C) Protons and electrons
(D) Protons, neutrons and electrons

Answer 1

Hint: A nucleon can be defined as one of the particles of the nucleus of an atom. Every nucleus contains one or more Nucleons. These nucleons are surrounded by one or more electrons. These entities occupy a small space inside the nucleus.

Complete step by step answer:
Until the 60s, nucleons were supposed to be elementary particles that are not constituted of smaller parts. Now they are called composite particles that are made of three quarks bound together by a so-called strong interaction. This interaction between the two or more nucleons is known as nuclear force.
Protons and neutrons when combined together are known as nucleons, as they are components of the atomic nucleus, they also exist as independent particles. Free neutrons are unstable. Their half-life is around 13 minutes, but they have other crucial applications.
The mass of a proton and neutron are the same: The weight of the proton is $$1.6726\times {10}^{-27}kg$$ while the mass of the neutron is $$1.6749\times {10}^{-27}kg$$. The neutron is $$0.13\mathrm{\%}$$ more heavier than proton. The similarity in mass is due to the similarity in masses of the quarks.
Atom is very much similar to a mini solar system, in which electrons orbit around a central star that is the nucleus which is composed of nucleons.
Nuclei are made up of neutrons and protons, but the mass of the nucleus is less than the sum of individual masses of the protons and neutrons combined together. The difference is the measure of binding energy per nucleon that holds the nucleons together.
Hence, Nucleons are protons and neutrons.

Therefore, option (B) is correct.

Note:
A Neutron is composed of one up quark and two down quarks. They are an integral part of the nucleus but they cannot exist as independent nucleons because the atomic nucleus holds them together with a strong force.