Your answer would be inside the nucleus.
There are three particles in an atom. Protons, neutrons, and electrons. Protons and electrons are both charged, with a positive and negative charge, respectively. Neutrons, on the other hand, are not.
Neutrons are found in the nucleus of the atom (along with protons, while electrons float around). Therefore, uncharged particles in an atom would most likely be found inside the nucleus.
Hope this helped!