Electronegativity of an element is related to ionisation energy and
Atomic radii
Electron affinity
Ionic radii
Nucleus
The electronegativity of any given element is not constant. It varies depending on the elements to which it is bound.
Though it is not measurable, it does provide a means to predict the nature of the force that holds atoms.
Electron affinity is energy that is released when an electron is added to an atom.
More electronegative elements more will be positive Electron affinity due to electron attraction. Halogen has the highest Electron affinity in a period.