What Is Electronegativity?
Electronegativity is a measure of the attraction of an atom for the electrons in a chemical bond. The higher the electronegativity of an atom, the greater its attraction for bonding electrons.
Electronegativity and Ionization Energy
Electronegativity is related to ionization energy
. Electrons with low ionization energies have low electronegativities because their nuclei do not exert a strong attractive force on electrons. Elements with high ionization energies have high electronegativities due to the strong pull exerted on electrons by the nucleus.
Electronegativity and Periodic Table Trends
In an element group, the electronegativity decreases as atomic number increases, as a result of increased distance between the valence electron and nucleus (greater atomic radius). An example of an electropositive (i.e., low electronegativity) element is cesium; an example of a highly electronegative element is fluorine.
- Moving left to right across the periodic table, electronegativity increases.
- Moving top to bottom down the periodic table, elctronegativity decreases.