Explanation:
For the given compound: (s)-3-iodo-2-methylnonane, only third carbon- atom (marked with red dot) is the chiral atom (as it is attached to 4 different substituents), so the configuration will be assigned to this C-atom only.
In assigning the configuration of this compound, the priorities are assigned based on their atomic masses. The lowest priority group ( that is Hydrogen) should lie on the vertical line. But here, it is lying on the horizontal line, so the configuration will be reversed.
The configuration coming out when H is on the horizontal line is R, but the actual configuration will be S.
The structure of the given organic compound is shown in the image attached.
