Iron (Fe) is a pure element, meaning it's made up of only iron atoms. It does not contain any oxygen atoms.

However, if you're asking about a compound containing iron and oxygen, like iron oxide (rust), then the number of oxygen atoms would depend on the specific type of iron oxide. For example:

* Iron(II) oxide (FeO): Has 1 oxygen atom per iron atom.

* Iron(III) oxide (Fe₂O₃): Has 3 oxygen atoms per 2 iron atoms.

Let me know if you have a specific iron compound in mind!