Protons and neutrons are subatomic particles that are found within the atomic nucleus. They are distinct from electrons, which are located in the electron cloud surrounding the nucleus.
Protons have a positive electric charge, with a charge of +1 elementary charge. They are relatively massive particles and contribute to the mass of the atom. The number of protons in an atom determines its atomic number, and each element has a unique number of protons. For example, hydrogen atoms have one proton, while carbon atoms have six protons.
Neutrons, on the other hand, are electrically neutral particles. They have no electric charge. Neutrons also have a significant mass, similar to that of protons. The number of neutrons in an atom can vary, even within the same element. Atoms of the same element that have different numbers of neutrons are called isotopes. Isotopes have the same number of protons (and hence the same atomic number), but different numbers of neutrons.
Together, protons and neutrons are known as nucleons. They are responsible for the vast majority of an atom's mass and are tightly bound together within the atomic nucleus by the strong nuclear force. Electrons, on the other hand, have much smaller masses and orbit the nucleus in specific energy levels or orbitals, forming the electron cloud.