The two particles in an atom that are equal in number are protons and electrons.

Here's why:

* Protons: Located in the nucleus of the atom, protons carry a positive charge. The number of protons defines the element.

* Electrons: Located in shells or orbitals around the nucleus, electrons carry a negative charge.

* Neutrons: Also located in the nucleus, neutrons have no charge.

In a neutral atom, the number of protons (positive charges) always equals the number of electrons (negative charges) to maintain a neutral electrical charge.