Question

Where can I find electronegativities of lithium, carbon, and fluorine? How do they relate to the tendency to obtain a noble gas configuration?

Answer 1

You can look this up in most common search results.

The EN of Lithium is 1.0, compared to Carbon's 2.5 and Fluorine's 4.0. That just reflects the idea that fluorine wants another electron the most and lithium wants to lose its electron the most in that particular periodic table row.

The relative ENs correlate with the number of valence electrons each atom on that row has, and because the number of valence electrons increases as you increase in atomic number on the same row (usually), the 'attractiveness' of pulling in new electrons to form a full octet is greater.