A couple of oldies, but goodies:

Two hydrogen atoms walk into a bar. One says to the other "hey, I think I lost an electron." His friend replies: "oh, are you sure?"

..."Yes, I'm positive."

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A hungry neutron has travelled many miles and finally takes a rest stop for some food and drink. He gobbles up voracious amounts of food and downs a pitcher or two. A little weary and ready to head home, the neutron asks the waiter "how much do I owe you?" "For you, my dear friend, no charge."

that first one...is hilarious.

This one is a little more colorful but hey we are all adults here.

Why is carbon considered to be the loosest element on the periodic table?

Because it will bond with just about anything!!