Question

Rank substituents in order of their priority when assigning the E or Z label to an alkene.

I, CH2I , H, CH2CH2Cl, F

Answer 1

We assign the priority to an atom or group of atoms based on selection rules

The selection rules are

a) the first priority is given to the group which is attached to double bonded carbon atom with highest atomic number element

so here we will give first priority to I and second to F

b) if same atoms are attached to double bonded carbon atom then the priority is assigned based on the next atom with highest atomic number

here we will give third priority to CH2I

c) after this the priority will be given to CH2CH2Cl

d) the least priority group will be hydrogen [least atomic number]

So the rank will be

I > F > CH2I > CH2CH2Cl> H