The number of the hydrogen atoms in a molecule of 6NH3 is 18.
Because 6 x 3 = 18
6NH3 = 6 ( Nitrogen Hydrogen 3)
So that would be 6 times 3 hydrogen the answer is 18.
Hydrogen atoms are the atoms of the chemical element hydrogen. It usually contains a single positive charge protons and single negative charge electrons. It do not have neutrons. It is called as protium with a symbol of 1H