The NH4 asked about is the amonium ion, and it's written NH4+ to indicate it has a positive charge (+1). It's a cation. Wikipedia has more information on this chemically â¦ significant polyatomic ion, and you'll find that a link to that post is provided below. + 7 others found this useful.
Gilbert is a town in Maricopa County, Arizona, United States, just southeast of Phoenix, within the Phoenix metropolitan area.
The City of Phoenix (black dot on the map) is in Maricopa County (white area). It is rather centrally located in the State of Arizona. Note that the map is not drawn to scale; these are simply general shapes and locations for your reference.