Electronegativity

electronegativity:  the tendency of an atom to attract electrons.

Pauling electronegativity scale:  a set of numbers that describe an element’s electronegativity.  (Named for Linus Pauling.)

Elements that “want” electrons pull harder, which makes them more electronegative.

· Atoms of elements farther to the right (except for noble gases) pull harder, because it’s easiset for them to get a full valent shell by gaining electrons.  Elements to the left pull the least hard.  (In fact, they don’t pull at all—they’re trying to get rid of electrons.)

· Atoms of elements higher up pull harder because they have fewer energy levels & sublevels to spread the electrons over, which makes it harder for them to be stable.

· Noble gases do not have electronegativities, because they neither “pull” electrons, nor “push” them away.

· Fluorine is the most electronegative element (3.98 on the Pauling scale).  Francium is the least electronegative element (0.7 on the Pauling scale).