why oxygen have high electronegative

Electronegativity is defined as the power of an atom to attract electron density to itself in a molecule.The electronegativity depends upon a number of factors.The first scale of electronegativity was developed by Linus Pauling and on his scale oxygen has a value of 3.44.
It is found that oxygen is the second most electronegative element after the fluorine which has the value of 4.0.In a period the value of electronegativity increases as we move from left to right.This is because atomic radius decreases when we move along a period.Smaller the value of atomic radius greater will be the electronegativity.Now as we move down the group,its value decreases because of effect of increased atomic radius.These reasons makes the oxygen an high electronegative element after the fluorine.