I'm not sure if you want the molecular formula or the condensed structure, but I will give you both.
Molecular formula:
You have 2 carbons (C₂), 4 hydrogens (H₄), and 1 oxygen (O). The molecular formula will be C₂H₄O.
Condensed Structure:
You have a carbon bonded to three hydrogens (CH₃). This carbon is bonded to a carbon that is bonded to a hydrogen and oxygen (CHO). The condensed structure will be CH₃CHO.
