Answer:
You could use a hydrogen anion which has 2 electrons.
Step-by-step explanation:
An ion is an atom or molecule with a net electric charge because it has more or less electrons compared to the original atom or molecule.
An anion is a negatively charged ion.
A cation is a positively charged ion.
Normally a hydrogen atom has one proton and one electron.
So a hydrogen anion (H-) means that it has one proton and two electrons, which means the positive charge will be +1 and the negative charge will be -2.
Ultimately, giving the entire molecule a net charge of -1 because -2+1 = -1.
(I hope this helps! I am not 100% sure what's the format of this question. Like is it interactive? online? Did you draw all those electrons on the diagram? or were they given? Are the numbers given as well? or did you type those in? So I just tried my best to give you something that might work.)