2 H 6 O but different structures. Ethanol is an alcohol and has an -OH group. In the modeling kit, the curved bonds are used used allow double bonds between atoms. Build models for diatomic oxygen and for carbon dioxide . Chains and rings.
Many organic molecules have chains of carbon atoms.
It is also common for atoms to form closed rings . Most drugs, for example, contain rings or 5 or 6 atoms. This is called cyclohexane . Many years ago chemists tried to create a molecule called cubane that would consist of a cube of 8 carbon atoms, with two hydrogens attached to each carbon. This proved not to be stable enough to isolate.