The Hydrogen Atom's Lament

A hydrogen atom and a helium atom go into a bar. The hydrogen atom is clearly upset and moans, "I've lost my electron, my only electron." The concerned helium atom says, "Just calm down now ... are you sure you've lost it?"

The hydrogen atom replies, "Yes, I'm positive!"

(Later, a neutron walks in to the same bar. He sits down and says to the bar tender, "Hey, how much for a beer?" The bar tender looks at him and says, "For you, no charge!")