benzene
Notice that the carbon chain forms a ring.
Further, note that each alternate carbon has a double bond to the next.
There are a total of 6 carbons and 6 hydrogens.
It is awkward to draw this all the time.
Below is a symbol way of drawing the benzene molecule.
Note that the double bonds are shown.
Here is yet another symbol way!
This is:
1-bromo-3-chlorobenzene
The numbering starts at the alphabetical bromo!