Ethane (CH3CH3 / C2H6) molecule contains two carbon atoms and six hydrogen atoms. In C2H6 lewis structure, all hydrogen atoms have made single bonds their respective carbon atoms. There are six C-H bonds in C2H6 lewis structure and no any lone pair exist on valence shells of carbon atoms.
Because there are eight atoms in C2H6 molecule, selection of center atom may be tricky. But, because hydrogen atom cannot be a center atom, carbon become the center atom. Because, there are two carbon atoms, both of carbon atoms should become center atoms.
Questions
Both ethene and ethane has two carbon atoms. Because ethene is an alkene compound, it should contain a double bond. So, difference of ethene's lewis structure is that having a double bond between two carbon atoms compared to ethane's lewis structure.