In the nucleus of the atom:
In the shell:
The easiest way to remember what charge they carry is by knowing that:
- Protons = Positive
- Neutrons = Neutral
- Electrons = Negative
The automic number shows the number of protons and electrons.
THESE ARE THE SAME.
The mass number tells us how many protons and neutrons in an atom.
The automic number for oxygen here is '8'.