1. First, examine the atoms directly attached to the stereocenter of the compound. An atom with a higher atomic number takes precedence over an atom with a lower number. Hydrogen is the lowest possible priority atom because it has the lowest atomic number.
   1. Ensure that the lowest priority group is pointed away (dashed back)
2. If two or more substituents have the same element directly attached to chiral carbon, proceed along the substituent chains until you find a point of difference. Determine which chain has the first connection to an atom with the highest priority (the highest atomic number). That chain has the higher priority.
3. For assigning priority, treat multiple bonds as if each bond of the multiple bond is bonded to a unique atom. For example, an alkene substituent (CH₂=CH-) has a higher priority than an ethyl substituent (CH₃CH₂-).

To identify the configuration of a stereocenter, you must identify if your order of priority goes in the clockwise or counterclockwise direction.

Clockwise = R
Counterclockwise = S

Bromine is the first priority (atomic number 35).
Oxygen is the second priority (atomic number 8).
Carbon is the third priority (atomic number 6).

It goes counterclockwise around the stereocenter.

Answer: S

Iodine is the first priority (atomic number 53).
Fluorine is the second priority (atomic number 9).
Carbon is the third priority (atomic number 6).

It goes clockwise around the stereocenter.

Answer: R

Hydrogen is wedged forward, so you must rotate the molecule or reverse the stereochemistry determined, as drawn below.

Hydrogen, the lowest priority group, is now dashed back.
Iodine is the first priority (atomic number 53).
Oxygen is the second priority (atomic number 8).
Carbon is the third priority (atomic number 6).

It goes counterclockwise around the stereocenter in the original figure.
It goes clockwise in the rotated molecule.

Answer: R