“I was going to make a joke about sodium, but Na”

The symbol for the chemical element Sodium is “Na,” prompting the popular joke:
 
“I was going to make a joke about sodium, but Na.”
 
“‘Hey, know any good jokes about sodium?’ ‘Na.’” was cited on Twitter on July 10, 2011. “I was going to tell you a joke about sodium… but na” was cited on Twitter on July 26, 2011.
 
   
Wikipedia: Sodium
Sodium /ˈsoʊdiəm/ is a chemical element with symbol Na (from Latin: natrium) and atomic number 11. It is a soft, silver-white, highly reactive metal and is a member of the alkali metals; its only stable isotope is 23Na. The free metal does not occur in nature, but instead must be prepared from its compounds. It was first isolated by Humphry Davy in 1807 by the electrolysis of sodium hydroxide. Sodium is the sixth most abundant element in the Earth’s crust, and exists in numerous minerals such as feldspars, sodalite and rock salt (NaCl). Many salts of sodium are highly water-soluble, and their sodium ions have been leached by the action of water so that sodium and chlorine (Cl) are the most common dissolved elements by weight in the Earth’s bodies of oceanic water.
     
Twitter
James E Lyon
‏@LyonJE
RT @ThatIsOdd “Hey, know any good jokes about sodium?” “Na.” (via @afreak)
10:31 PM - 10 Jul 2011
 
Twitter
@x_micaah
“Want to hear a joke about sodium?” “Na”
5:01 AM - 11 Jul 2011
 
The Best Deceptions
Monday, July 25, 2011
“Do you want to hear a joke about sodium?” “Na.”
 
Twitter
Anelia Varela
‏@aneliavarela
I was going to tell you a joke about sodium… but na
3:31 PM - 26 Jul 2011
 
Twitter
TheJosenPeople
‏@TheJosenPeople
I wanted to write a joke about sodium, but NA.
9:19 AM - 27 Jul 2011
 
Twitter
Faye Tan
‏@sushifaye
Wanna hear a joke about potassium?
K.
Wanna hear a joke about sodium?
Na.
I’d tell you a good chemistry joke, but all the good ones argon.
10:44 PM - 19 Dec 2011
     
Google Books
The Mammoth Book of One-Liners
By Geoff Tibballs
London: Constable & Robinson Ltd.
2012
Pg. ?:
Do you want to hear a joke about sodium?
Na.
   
Google Groups: IVBCF Sistahood ‘11 - ‘12
BANdwagon Business—Please respond by Friday!
Connie Lam
2/23/12
(...)
“Did you hear that joke about sodium? Naaaaaaaa.
“What about that joke about sodium bromide?” “Na, Bro.”
   
Google Books
More One Liners, Jokes and Gags
By Grant Tucker
London: The Robson Press
2013
Pg. ?:
Want to hear a joke about sodium? Na
 
Business Insider—Australia
Here Are 15 Jokes Only Chemists Will Get
KELLY DICKERSON, JENNIFER WELSH OCT 21 2013, 4:02 AM
(...)
Q: Anyone know any jokes about sodium? A: Na.
Explanation: The symbol for sodium on the periodic table is “Na,” which when said as a word is pronounced like nah, another way to say no.
   
Washington (DC) Post
Popular Science readers’ favorite science jokes
By Nancy Szokan March 31, 2014
(...)
Chemistry. I was going to tell a joke about sodium, but Na.
@IanHaygreen