Respuesta :

joeschmoef46
 2 Nitrogen, 4 Hydrogen, 3 Oxygen 

9 atoms per molecule. 

NH4, ammonium (not to be confused with ammonia NH3) is a 1+ ion and NO3 is 1-. 
1 atom of N, 4 atoms of H, 1 atom of N again, and 3 atoms of Oxygen. Combine that and you have 2 atoms of N, 4 of H, and 3 of Oxygen. Hope that helps!