Electronegativity: The Pauling scale is the most commonly used system for electronegativity, and most complete electronegativity lists use it. These lists also put francium as the lowest electronegativity with 0.7. However, some of the reported values may be estimated rather than calculated. The Allen scale may be a more complete system, and it places caesium as the least electronegative element. However, it is difficult to find lists of Allen electronegativity values to confirm this. There seems to be no one source which says all of that, so for now, the Pauling value will remain, unless a better source can be found.
Some of the text in this entry was rewritten from Los Alamos National Laboratory - Francium. Additional text was taken directly from the Elements database 20001107, and Webster's Revised Unabridged Dictionary (1913). Other information was obtained from the sources listed on the main page but was reformatted and
I am no expert in this subject, but maybe we could change the phrase "making it possibly the rarest elements in the crust, along with astatine." to "making it one of the rarest elements in the crust, next to astatine." See astatine talk page for more info.
A reminder: in the infobox, we need to explain the question marks like in "? 300 K" (it's an FA). In a few days time we can use the |melting point comment= for this. While I am here, let me note that I do not understand the lede part "and actinium K". Both the link and the "K" do not give clarification. -DePiep (talk) 12:33, 28 July 2014 (UTC)
I went ahead and stuck a picture of Marguerite Perey in this article, but it turns out that it might not be fair use according to the wikimedia page. Suggestions? Mr.Magik-Pants (talk) 16:55, 11 March 2015 (UTC)