* 3NH3 means there are three ammonia molecules.

* NH3 represents one ammonia molecule. It contains:

* 1 nitrogen atom (N)

* 3 hydrogen atoms (H)

Therefore, in three ammonia molecules (3NH3), there are:

* 3 nitrogen atoms (3 x 1 = 3)

* 9 hydrogen atoms (3 x 3 = 9)

In total, there are 12 atoms in the molecule 3NH3.