Electronegativity, EN, is an index that tells the relative attraction an element has for electrons in a bond. Electronegativity has a high value of 4.0 for F, fluorine. The lowest electronegativity value is about 0.7 for Cs, cesium. The table below shows the nonmetals have relatively high electronegativities. The metals have relatively low electronegativities.
Electronegativity gets smaller with increasing distance from fluorine.
The rare gases generally are not tabulated for EN values. Bond polarity is directly related to electronegativity difference. The greater the difference in electronegativity the more polar the bond. When two elements are next to one another in the periodic table they have similar electronegativities. Chlorine has a value of 3.0 while bromine has a value of 2.8.