The term nucleus is used to describe the center of something, usually an atom or a cell; it could be used to describe the center of a city as well.
City hall
in the nucleus
in the nucleus of a cell
In the nucleus.
only eukaryotic cells have a nucleus if it is prokaryotic cells don't have nuclei
If I understand your question correctly, then it would be the mayor.
outside the nucleus in the electron cloud
the nucleus
Normally, for most cells the nucleus would be found in the center, and all cells have a nucleus, which contains DNA on chromosomes
If you're referring to the nucleus of an atom, the answer is electrons.
You can find a proton in the nucleus of the atom along with neutrons.
You would find them in a nucleaus inside the cell.