Two hydrogen atoms were walking down a dark alley...

As I was commenting on another photo I was reminded of a joke my high school chemistry teacher told us in class one day. I hate to admit that I actually thought it was funny, although in a painful sort of way.

(I didn't find an alley to take a picture of so here's the creepy emergency exit for the parking garage in my apt building).

Two hydrogen atoms were walking down a dark alley.
The first turns to the second and says, “I think I lost an electron.”
The second asks, “Are you sure?”
“I’m positive.”

Ha. Ha. Ha. (Groan)