Knowledge database: 1.14 Electronegativity

Electronegativity is a measure of the strength with which the atoms of an element attract electrons. This measure is important in the domain of covalent bonds where there is always an atom that attracts electrons stronger (and therefore has higher electronegativity) than other atom(s) (because of their lower electronegativity). The values are displayed numerically using the electronegativity coefficient. The most electronegative element, fluorine, has the value of -4. The coefficient of the least electronegative element, cesium, is 0.7. As a rule, electronegativity coefficients grow from the lower left corner of the periodic table of elements to the upper right corner, what we can see in the picture below.

It is also important to mention that on the basis of differences between electronegativity coefficients of elements, i.e. atoms that are included in the composition of a compound, we can determine the nature of bonds between these atoms. According to the American chemist Linus Pauling, differences between electronegativity coefficients smaller than 1.9 point to a greater covalent character of the bond, while the difference higher than 1.9 points to a greater ionic character of the bond.