Yes, atoms of any element contain only that element. It is impossible to have an impure atom.
Iron, being a metal does not form molecules. Being an element it consists entirely of iron atoms.
The atoms in iron are little groups that act like tiny magnets also found in nickle and cobalt!
There are 26 protons in the nucleus of an iron atom. The number of neutrons will vary depending on which isotope of iron we consider. And there are 26 electrons in a neutral atom of iron.
nothing yust instead of having Fe you have FeO or Fe2O3