Question

what is the constitution of a neutron

Answer 1

Protons and neutrons constitute the nuclei of atoms. Since protons andneutrons behave similarly within the nucleus, and each has a mass of approximately one atomic mass unit, they are both referred to as nucleons. ... Neutrons are required for the stability of nuclei, with the exception of the single-proton hydrogen atom.

Answer 2

Protons and neutrons constitute the nuclei of atoms. Since protons and neutrons behave similarly within the nucleus, and each has a mass of approximately one atomic mass unit, they are both referred to as nucleons.
Neutrons are required for the stability of nuclei, with the exception of the single proton hydrogen atom.