What is the electronegativity of an element?
Electronegativity is the tendency of an atom/element to attract a shared pair of electrons towards itself.
Suppose A bond is formed as a result of chemical reaction between H and Cl and electrons are shared . Now, as Cl is more electronegative than H it will pull the electron of H towards itself more. This is known as electronegativity or you can say Cl is more electronegative as compared to H. hope this helps thanks