Answer
The intermediate is on the left of the image:
Work Step by Step
1. Analyze the arrow.
- It is breaking the bond between the "Br" and the compound.
Therefore, now there will be the compound without the "Br", and the "Br" alone, because they got separated. (Tail)
- It is giving the electrons from the bond to the "Br".(Head)
2. Now, let's find the formal charges:
"Br": Initially, it had 6 electrons in lone pairs, and it received one new pair from the arrow. So, now it has 8 electrons and no bonds, since a neutral "Br" has 7: "7 - 8 = -1". Therefore, its formal charges is "-1".
The carbon that was making the bond with the "Br": Initially, it had 4 bonds and no free electrons, and then it lost a bond. Therefore, it has, now, 3 bonds, and it has a formal charge of "+1".
