As an ion chromatography chemist I made this one up: Anions aren't negative, they're just misunderstood.
 1899
1  

Why did the Mexican take Xanax? For hispanic attacks.
 1323
0  

Chuck Norris destroyed the periodic table, because Chuck Norris only recognizes the element of surprise.
 750
0  

Q: Why was the mole of oxygen molecules excited when he walked out of the singles bar? A: He got Avogadro's number!
 1926
5  

Two chemists go into a restaurant. The first one says "I think I'll have an H2O." The second one says "I think I'll have an H2O too" - and he died.
 816
0