Final answer:
The formula 3NH4 consists of two different elements, nitrogen and hydrogen, with a total of 3 nitrogen atoms and 12 hydrogen atoms across three ammonium ions.
Step-by-step explanation:
The compound represented by the formula 3NH4 implies that there are three molecules (instances) of the ammonium ion. Each ammonium ion (NH4+) consists of one nitrogen (N) atom and four hydrogen (H) atoms. To calculate the total number of elements in the given formula, multiply the number of each type of atom in one ammonium ion by the three ammonium ions present:
Nitrogen: 1 atom × 3 = 3 nitrogen atoms
Hydrogen: 4 atoms × 3 = 12 hydrogen atoms
Therefore, there are two different elements present in 3NH4, but there are fifteen individual atoms in total when considering three entities of the ammonium ion.
The correct answer to how many elements are there in 3NH4 would be two, option 2).