The particle smaller than an atom and with zero electric charge is a neutron.

Here's why:

* Atoms are the smallest unit of an element that retains the chemical properties of that element. They are made up of even smaller particles.

* Neutrons are one of the particles found in the nucleus of an atom. They have no electric charge (they are neutral).

* Protons are the other particles found in the nucleus. They have a positive electric charge.

* Electrons orbit the nucleus and have a negative electric charge.

Let me know if you have any other questions!