Here's how to figure out the number of atoms in a molecule of laughing gas (nitrous oxide, N₂O):

* Chemical Formula: Laughing gas has the chemical formula N₂O.

* Subscripts: The subscripts tell us how many atoms of each element are in the molecule:

* N₂ means there are 2 nitrogen atoms

* O means there is 1 oxygen atom

Therefore, there are a total of 3 atoms in a molecule of laughing gas (2 nitrogen + 1 oxygen).