Question

Nitrogen, oxygen, and fluorine have higher
electronegativity due to?

Answer 1

Fluorine is a higher electronegativity 
The electronegativity of F is greater than O due to the reason that F has 1 more proton in its nucleus than O and having small size than O.


Fluorine is having very small size and effective nuclear charge is very high in fluorine

Answer 2

nitrogen, oxygen & fluorine have higher electronegativity due to
they gain electrons more easily
nitrogen has a atomic number-7 so the in the last shell it has 5 electron so to become stable it gain 3 electron to become stable
oxygen has 8 atomic number so the outermost shell has 6 electron so to become stable it gain 2 electron
fluorine has a atomic number 9 so the outermost shell has 7 electron to become stable it has to gain 1 electron
hope this will help you