1. Ionic Addition animation
Addition of HBr to ethene shown
Similar for addition of
Br2 and
Cl2 and
HCl

2. Press F5 to start Note the pi bond above and below the sigma bond
Note how charges change from partial charge (  +) to full charge – ions.
Also watch for the fact that HBr (or HCl) is polar at the start while Br2 and Cl2 become polar as they approach the double bond – region of negative charge
Press F5 to start

3. HBr to any C=C double bond
Ionic addition
HBr to any C=C double bond
Also applies for Br-Br and Cl-Cl