* Protons: Positively charged particles found in the nucleus of the atom.

* Neutrons: Neutrally charged particles also found in the nucleus of the atom.

* Electrons: Negatively charged particles that orbit the nucleus in a cloud-like region called the electron cloud.

Here's a breakdown of their relative sizes and contributions to the atom's overall structure:

* Protons and neutrons: These particles are much heavier than electrons and make up almost all the mass of an atom. They are located in the atom's central region, called the nucleus.

* Electrons: These particles are much lighter than protons and neutrons and are responsible for the atom's chemical properties. They occupy a much larger volume of space around the nucleus, forming the electron cloud.

While the vast majority of an atom's volume is empty space occupied by the electron cloud, it's important to remember that almost all the mass of an atom is concentrated in its tiny nucleus where the protons and neutrons reside.