What are the 3 compounds of an atom?

Answer 1

This question does not seem to make sense in its present wording.

If you are asking what are the three basic particles that make up an atom, they are the electron, the proton and the neutron.

The protons and neutrons form the nucleas (center) of the atom and are considered to comprise most or all of its weight (mass). The electrons circle around the nucleas in orbits called "shells" and are considered to be responsible for the reactivity of the atom with itself or with other atoms. They contribute nothing, or nearly nothing, to the Atomic Mass.

Answer 2

The three main constituents of an atom are protons, neutrons, and electrons. Protons and neutrons are located in the nucleus, with protons carrying a positive charge and neutrons carrying no charge. Electrons orbit around the nucleus and have a negative charge.