Answer:
positve 1
Step-by-step explanation:
Since the Nitrogen is a neutral atom when is in it basic form. Tend to loose 3 electrons, that is the reason why it has a valence of 5, this means that are 3 available places for positives charges, to complete the octet, and to be neutral again.
In the case of ammonium, since the Nitrogen receives 4 positives charges, one positive charge from each Hydrogen atom, the amount of positive charges are more than the negative charges. That is the reason the ammoniun has 1+. NH4 1+