what is an electronegative element
The opposite of electronegativity is electropositivity: a measure of an element's ability to donate electrons. Caesium is the least electronegative element in the periodic table (=0.79), while fluorine is most electronegative (=3.98).(Francium and caesium were originally assigned both assigned 0.7; caesium's value was later refined to 0.79, but no experimental data allows a similar refinement for francium.roperties of a free atom include ionization energy and electron affinity. It is to be expected that the electronegativity of an element will vary with its chemical environment, but it is usually considered to be a transferable property, that is to say that similar values will be valid in a variety of situations.