- Have a mass. (9.10938188×10−31 kilograms), though this can sometimes be considered negligible due to how small that actually is. Barely factored into atomic mass
- Negatively charged
- Found outside the nucleus in the electron shell
Neutrons:
- Have a mass
- Neutral (no charge)
- Found inside the nucleus of an atom
Atom A:
- 1 proton
- 0 Neutrons
- 1 electron
- Atomic mass of 1
- Atomic number of 1
Atom B:
- 8 Protons
- 10 Neutrons
- 8 electrons
- Atomic mass of 18
- Atomic number of 8
Atomic mass includes the number of protons and neutrons in the nucleus. Atomic number is the number of protons, as this is what defines what type of element the atom is.
