You need to specify which lead oxide you're asking about, as there are multiple:

* Lead(II) oxide (PbO): This has 2 atoms per molecule, one lead (Pb) atom and one oxygen (O) atom.

* Lead(IV) oxide (PbO₂): This has 3 atoms per molecule, one lead (Pb) atom and two oxygen (O) atoms.

Please clarify which lead oxide you are referring to.