The most space of an atom is vacuum.
The protrons and the neutrons take up the most space in a atom.The nucleus takes up the majority of the atoms mass but the majority of the atom at about 99.99% of the atom is actually empty space.
The electron cloud that contains the electrons outside the nucleus takes up the most space of the atom.
The "Electron Shell" by the current model takes up the most space due to its location in any given place along a series of orbits, but has the least mass.
Technically, the term particle here is incorrect. The distinction must be made between particle (the things that make up elements and compounds) and sub-atomic particles. (the things that make up elements) In an atom, the sub-atomic particle occupying the most space is the nucleus, containing protons and almost always, neutrons. The rest of it is empty space, save for the orbiting electrons, which are quite tiny in comparison to the nucleus.
The electrons
A great, great amount of empty space. I refer you to the link attached.
The valence electrons are the part that takes place in a chemical reaction.
Only the valence electrons
After the space shuttle takes off, it goes into outer space. The astronauts in the space ship keep in contact with the people in case they need help, but are on their own for the most part.
He is best known for his new model of the atom. He performed the alpha scattering experiment and concluded that the nucleus is positively charged, very dense and makes up a very small part of the atom such that most of an atom is empty space.
Almost all of the volume of an atom is the space between the nucleus and the electrons.
The space surrounding the nucleus.