Answer:
1. Identity of the atom, matchs with Proton.
2. Chemical behaviour of atom, matchs with Electron.
3. Acts as buffer between protons in nucleus to help stabilize nucleus and add mass to atom, matchs with Neutron
Step-by-step explanation:
Protons are subatomic particles located in the nucleus, that has a possitive charge and that never change (number of protons remains always the same for a particular element). Because of this property are considered the identity of an atom and defines a constant variable called atomic number.
Electrons are another kind of subatomic particles that are located outside the nucleus and does not contribute with significan amount of mass to the atom. This kind of particles, freely moves around the nucleus and are responsibles for the interaction and formation of bonds between elements (it means of their chemical behaviour).
Neutrons are also located in the nucleus and signifficantly contributes to the total mass of an atom. The sum of neutrons and protons constitute the mass number of an atom.