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.
Flagstaff is a city in and the county seat of Coconino County in northern Arizona, in the southwestern United States. In 2015, the city's estimated population was 70,320. Flagstaff's combined metropolitan area has an estimated population of 139,097.