A photon is not composed of an electron, a proton, and a neutron. Instead, a photon is itself one of the fundamental particles in the Standard Model of particle physics.
In the Standard Model, photons are considered elementary particles, meaning they are not composed of smaller particles. They are classified as gauge bosons, specifically the force-carrying particle associated with the electromagnetic force. Photons have no electric charge and no mass. They are the quantum carriers of electromagnetic radiation, including visible light, radio waves, microwaves, X-rays, and gamma rays.
On the other hand, electrons, protons, and neutrons are composite particles. Electrons are elementary particles and have a negative electric charge. Protons and neutrons, on the other hand, are composite particles called hadrons, consisting of quarks bound together by the strong nuclear force. Protons have a positive electric charge, while neutrons are electrically neutral.
It's important to note that photons and particles like electrons, protons, and neutrons belong to different categories in the Standard Model. Photons mediate the electromagnetic interaction, while electrons, protons, and neutrons participate in other fundamental forces and interactions.