Why is the electronegativity of nonmetal higher than metal?

Answer 1

All metal has less number of proton when compared to non-metal,

in another word all metal has low effective nucleus charge compared to non-metal,

the high effective nucleus charge causes the non-metal has higher electronegative than metal as the term electronegative means the ability to accept electron from others and in order to do that the nucleus of the atom

( effective nucleus charge ) must be high enough.

That explain why metal donate electron due to low electronegative and non-metal accept electron due to high electronegative.

Answer 2

Nonmetals have higher electronegativity than metals because nonmetals have a higher tendency to attract electrons due to their higher effective nuclear charge and smaller atomic radii. This makes nonmetals more electronegative, whereas metals have lower electronegativity because they have a lower tendency to attract electrons and instead prefer to lose electrons to form positive ions.