Determine the total valence electrons for all atoms indicated in the given molecular formula. If there is a negative charge add one electron to the total for every negative charge. If there is a positive charge indicated on the molecular formula subtract one electron for every positive charge indicated. In this compound there would be 3 carbons for 12 and 6 Hydrogens for 6 more or a total of 18 valence electrons total. Determine which atom or atoms will be in the center.
Carbon atoms are tetravalent, and therefore, can have four bonding pairs around each carbon atom.
Therefore, these carbon atoms would be in the center and the hydrogens would be distributed as symmetrical as possible around them. Using the valence electrons available from step 1, connect all the atoms together in one cohesive unit using bonding pairs symbolized by a dash for each bonding pair. Check each atom to see if it obeys the Octet Rule which says that an atom in order to be the most stable must have eight valence electrons with the exception of Hydrogen which must have only two electrons in their valence region to be stable. Each Hydrogen obeys the Octet Rule having the required two electrons. It is possible to move Hydrogens along with their bonding pairs of electrons from one carbon to another.