* 5 atoms of Hydrogen (H)

* 2 atoms of Nitrogen (N)

* 2 atoms of Oxygen (O)

Here's how to break it down:

* Ammonium (NH₄⁺): This part has 4 hydrogen atoms and 1 nitrogen atom.

* Nitrite (NO₂⁻): This part has 1 nitrogen atom and 2 oxygen atoms.

When these ions combine to form ammonium nitrite, the molecule contains a total of 5 hydrogen atoms, 2 nitrogen atoms, and 2 oxygen atoms.