Here's how to break down the chemical formula for dinitrogen pentoxide:

* Dinitrogen: "Di" means two, so there are two nitrogen atoms (N).

* Pentoxide: "Penta" means five, and "oxide" refers to oxygen. Therefore, there are five oxygen atoms (O).

So, the compound dinitrogen pentoxide (N₂O₅) contains:

* 2 nitrogen atoms (N)

* 5 oxygen atoms (O)