The Feynman diagram shows two electrons approaching each other, interacting, and then leaving each other. What particle is being exchanged during the interaction? A positively charged electron is"

Elementary particles, also known as fundamental particles, are subatomic particles that are not made up of other particles. They are smaller than an atom and do not appear to be made up of a combination of more basic things. 
The Standard Model recognizes 17 distinct particles, including 12 fermions and five bosons.