I believe it would be weight. mass never changes.
Answer:
idk butttttt.... i had fun talking to u yesterday and the other conversation is getting a little....uhm....how do i say this.....weird.....everyone is friends now¯\_('-')_/¯
Explanation:
Within an atom, there are three elementary particles: the proton, neutron, and electron. Most of the mass of an atom is situated within the nucleus, which is the central part of the atom. It is made up of protons and neutrons, which are the heaviest subatomic particles. The electrons within the atom, orbit around the nucleus at a very far distance. Electrons are also a part of the lightest group of subatomic particles called leptons. That is why these electrons don't contribute much to the majority of an atoms mass. They are very light and they orbit at very far distances.