Naming HaloAlkanes (1 Viewer)

[Robbie M]

Hey guys, im having some trouble with the formalities of naming haloalkanes.
I understand when writing down the name, you do it in alphabetical order, however, how do u decide which end of the haloalkane to start counting from if Eg Cl is at one and F at the other etc, is there a rule?

http://conqchem.cci.net.au/Fig7.4Revised.gif

I don't understand how in the bottom role of that ^^ picture bromo is counted first, then in the second fluro and then choloro this doesn't follow alphabetically or electromagnetically ( what i previously thought) please help

Thanks

 

[jazz519]

the alphabetical is for the suffix (the bromo or chloro etc.) the prefix which lists how many such tri or di isn't what we look at alphabetically.

You gotta try do two things, get them in alphabetical and the lowest number overall from adding where the chloro etc are on the molecules

 

[Robbie M]

Yea i get that, but if you have two different atoms on each end of a molecule, which end do u start numbering from first

 

[jazz519]

Yea i get that, but if you have two different atoms on each end of a molecule, which end do u start numbering from first

the alphabetical one if you can (most of the time has the lowest number), but just write out both and see which one adds up to lowest