The model of a molecule composed of two carbon atoms and four hydrogen atoms refers to the molecule ethane, which can be represented as:
H H
\ /
C
/ \
H C
\
H
This structure indicates that there are two carbon atoms (C) and four hydrogen atoms (H).
The chemical formula for this substance, ethane, is C₂H₆. However, it is possible that you are looking for a different molecule that fits the criteria of having two carbon atoms and four hydrogen atoms, but with a different structure, such as butene. If so, the correct molecular structure for two carbon atoms and four hydrogen atoms is:
C₂H₄
If the specified molecule is indeed correct as ethane, then the chemical formula would be C₂H₆. If you need to select based on conventional names or structures, please provide more context on the specific structures or options presented.