As you know, the ratio of protons to electrons will determine if an atom is neutral or if it carries an overall net charge.
More specifically, you have three possible scenarios to consider
- if you have equal numbers of protons and of electrons
#->#the atom will be neutral
- if you have more protons than electrons
#->#the atom will have an overall positive charge
- if you have more electrons than protons
#->#the atom will have an overall negative charge
So, you know that you have
A neutral copper atom will thus have
To form a positively charged ion, or cation, you can keep the number of electrons constant and add one or more protons to the nucleus.
If you add one proton, you'll end up with
Since you now have an extra proton compared to the number of electrons, you'll end up with a
Adding two protons will get you to gallium,
This time, you have two extra protons compared with the number of electrons, so the overall charge will be