How does a person know where their body parts are located, (nose, mouth, etc.) without looking? such as eating popcorn without taking eyes off movie.

It's called "hand eye coordination" although the statement implies that you must be watching where to put your hands,  thats not always true. And because you have had the same parts your whole life, unless something bad happened or you're just caitlyn (bruce) Jenner.

The proton has a positive charge while the neutron has no charge they both make up the nucleus of the atom while the elections have a negative charge and surround the nucleus of the atom. the protons and electrons are used to calculate the atom's mass whereas the neutrons don't affect the mass