Neutrons and * blank * are found in the nucleus of an atom

I think it's protons

Protons.

Explanation:

The different structure of the atoms are discovered by the different scientists to explain the atom structure. Three sub atomic particles of the atom are electron, proton and neutron.

The electrons revolve around the nucleus in the fixed orbit. The protons and neutrons are present inside the nucleus of the atom. The protons and electrons are equal in the atom.

Thus, the answer is proton.