umm thanks. i didnt know this -gen rule.. thankeeNo ! .. nor are any other Ionic/Covalent compounds .. the only diatomic elements are those elements which end in -gen ( that's how i remember it)
-Halogens
-Nitrogen N2
-Oxygen O2
-Hydrogen H2
The compounds containing these elements are not diatomic either .. only these elements exist in diatomic form.
Like Potassium exists as K in nature , similarly Nitrogen and other diatomic elements occur in N2 form instead of N.
Depends on the way which that word is used really .. Diatomic can also mean a compound containg 2 atoms .. in which case what you have written will be correct , but i don't think the question which snowboard asked would be about that.
PS: I have edited my post to change it , thanks glamgurl for pointing it out