Electronegativity trends in the periodic table
Electronegativity is the tendency of an atom to shift the electron density in a chemical bond towards itself. The electronegativity of an element increases with atomic number and decreases with the atomic size. The atomic number increases when we go down and the atomic size decreases from left to right in the periodic table. As a result, the elements found in the top right corner, bar the noble gases, have the highest electronegativity values. From this trend, we can comfortably predict that the most electronegative element is fluorine, followed by oxygen and then nitrogen.
Figure 1: Periodic table of elements showing the elements' relative electronegativity values