In C2H4Cl2 is it correct that I cannot write this structural formula as a ring because halogens can only have one shared bond? Otherwise if the formula is CnH2n then I would be able to draw a ring for the structure?
you are right, C2H4Cl2 will not form a ring. You need a minimum of 3 atoms to form a ring, and all three atoms have to have the ability to form at least two bonds.
CnH2n will be able to form rings for all n>3. However, not all rings have to be CnH2n
the given molecular formulas? Does anyone have a strategy that I can use? Would I just write the unbranched structural formulas and follow it by branching starting from the earliest point in the structure? So for C5H12 write the unbranched structure and take it from there?
the best strategy, I think is practice, the more carbon atoms the larger the number of choices. But it always helps to at least try branching one at a time.
so starting with 5 carbons begin with a 4 carbon chain and 1 branch on the second.
move the branch down each carbon until you end up with a repeat. branching 1 carbon on the second is the same as a branch on the 4th.
then 3 carbon chain with a 2 carbon branch. move the branch. then 2 branches of one carbon each. so on and so forth.
